完善AMESim组件界面与仿真求解稳定性

app/main.py

@@ -641,6 +641,11 @@ def run_system_xml_simulation(
                 t_start=project.simulation.t_start,
                 t_stop=project.simulation.t_stop,
                 method=project.simulation.method,
+                # The pressure-flow closure is solved to a scaled 1e-7
+                # residual.  Asking the outer adaptive integrator for 1e-6
+                # relative accuracy makes its finite-difference Jacobian chase
+                # algebraic solver noise after discontinuous signal events.
+                rtol=1.0e-5,
                 max_step=project.simulation.max_step,
             ),
             sample_step=project.simulation.step,

app/simulation/components/amesim/boundary/sources.py

@@ -26,7 +26,7 @@ class AmesimPnpl01(AlgebraicComponent):
         label="PNPL01 零气动流边界",
         library_id="amesim",
         category_id="boundary",
-        symbol="generic",
+        symbol="amesim_pnpl01",
         ports=(PortDisplaySpec("port_1", "left", order=10),),
         order=10,
     )

app/simulation/components/amesim/flow/orifices.py

@@ -105,7 +105,7 @@ class AmesimPnor001(AlgebraicComponent):
         label="PNOR001 常系数气动孔口",
         library_id="amesim",
         category_id="flow",
-        symbol="orifice",
+        symbol="amesim_pnor001",
         ports=(
             PortDisplaySpec("port_1", "left", order=10),
             PortDisplaySpec("port_2", "right", order=20),
@@ -412,7 +412,7 @@ class AmesimPnvo001FixedOpening(AlgebraicComponent):
         label="PNVO001 固定开度气动孔口",
         library_id="amesim",
         category_id="flow",
-        symbol="orifice",
+        symbol="amesim_pnvo001_fixed",
         ports=(
             PortDisplaySpec("port_2", "left", order=10),
             PortDisplaySpec("port_3", "right", order=20),
@@ -633,7 +633,7 @@ class AmesimPnvo001SignalOpening(AmesimPnvo001FixedOpening):
         label="PNVO001 信号开度气动孔口",
         library_id="amesim",
         category_id="flow",
-        symbol="orifice",
+        symbol="amesim_pnvo001",
         ports=(
             PortDisplaySpec("res", "left", order=5),
             PortDisplaySpec("port_2", "left", order=10),

app/simulation/components/amesim/flow/pipes.py

@@ -105,7 +105,7 @@ class AmesimPnl00r(AlgebraicComponent):
         label="PNL00R 气动管路阻力",
         library_id="amesim",
         category_id="flow",
-        symbol="pipe",
+        symbol="amesim_pnl00r",
         ports=(
             PortDisplaySpec("port_1", "left", order=10),
             PortDisplaySpec("port_2", "right", order=20),
@@ -440,7 +440,7 @@ class AmesimPnl0001(ThermodynamicVolumeComponent):
         label="PNL0001 C-R 动态管路",
         library_id="amesim",
         category_id="flow",
-        symbol="pipe",
+        symbol="amesim_pnl0001",
         ports=(
             PortDisplaySpec("port_1", "left", order=10),
             PortDisplaySpec("port_2", "right", order=20),
@@ -720,7 +720,7 @@ class AmesimPnl0002(AmesimPnl0001):
         label="PNL0002 R-C-R 动态管路",
         library_id="amesim",
         category_id="flow",
-        symbol="pipe",
+        symbol="amesim_pnl0002",
         ports=(
             PortDisplaySpec("port_1", "left", order=10),
             PortDisplaySpec("port_2", "right", order=20),
@@ -920,7 +920,7 @@ class AmesimPnl0003(DynamicComponent):
         label="PNL0003 C-R-C 动态管路",
         library_id="amesim",
         category_id="flow",
-        symbol="pipe",
+        symbol="amesim_pnl0003",
         ports=(
             PortDisplaySpec("port_1", "left", order=10),
             PortDisplaySpec("port_2", "right", order=20),

app/simulation/components/amesim/junctions/nodes.py

@@ -91,7 +91,7 @@ class AmesimPn3Node2(_AmesimPneumaticNode):
         label="PN3NODE2 三端气动节点",
         library_id="amesim",
         category_id="junctions",
-        symbol="tee",
+        symbol="amesim_pn3node2",
         ports=(
             PortDisplaySpec("port_1", "left", order=10),
             PortDisplaySpec("port_2", "right", order=20),
@@ -128,7 +128,7 @@ class AmesimP4Node2(_AmesimPneumaticNode):
         label="P4NODE2 四端气动节点",
         library_id="amesim",
         category_id="junctions",
-        symbol="generic",
+        symbol="amesim_p4node2",
         ports=(
             PortDisplaySpec("port_1", "left", order=10),
             PortDisplaySpec("port_2", "right", order=20),

app/simulation/components/amesim/mechanical/translational.py

@@ -22,7 +22,7 @@ class AmesimF000(AlgebraicComponent):
         label="F000 零力源",
         library_id="amesim",
         category_id="mechanical",
-        symbol="generic",
+        symbol="amesim_f000",
         ports=(PortDisplaySpec("port_1", "right", order=10),),
         order=10,
     )
@@ -73,7 +73,7 @@ class AmesimForc(AlgebraicComponent):
         label="FORC 信号转力",
         library_id="amesim",
         category_id="mechanical",
-        symbol="signal",
+        symbol="amesim_forc",
         ports=(
             PortDisplaySpec("res", "left", order=10),
             PortDisplaySpec("port_2", "right", order=20),
@@ -167,7 +167,7 @@ class AmesimMecmas21(DynamicComponent):
         label="MECMAS21 一维质量",
         library_id="amesim",
         category_id="mechanical",
-        symbol="generic",
+        symbol="amesim_mecmas21",
         ports=(
             PortDisplaySpec("port_1", "left", order=10),
             PortDisplaySpec("port_2", "right", order=20),
@@ -323,7 +323,7 @@ class AmesimLstp00a(AlgebraicComponent):
         label="LSTP00A 弹性接触",
         library_id="amesim",
         category_id="mechanical",
-        symbol="generic",
+        symbol="amesim_lstp00a",
         ports=(
             PortDisplaySpec("port_1", "left", order=10),
             PortDisplaySpec("port_2", "right", order=20),
@@ -425,7 +425,7 @@ class AmesimLmechn1(AlgebraicComponent):
         label="LMECHN1 线性机械节点",
         library_id="amesim",
         category_id="mechanical",
-        symbol="junction",
+        symbol="amesim_lmechn1",
         ports=tuple(
             [PortDisplaySpec(f"port_{index}", "left", order=index * 10) for index in range(1, 9)]
             + [PortDisplaySpec("port_9", "right", order=90)]

app/simulation/components/amesim/signals/sources.py

@@ -1,6 +1,7 @@
 from __future__ import annotations
 
 from collections.abc import Mapping
+from math import floor
 
 from app.simulation.core.base import AlgebraicComponent
 from app.simulation.core.catalog import ComponentDisplaySpec, PortDisplaySpec
@@ -27,7 +28,7 @@ class AmesimStep0(AlgebraicComponent):
         label="STEP0 阶跃信号",
         library_id="amesim",
         category_id="signals",
-        symbol="signal",
+        symbol="amesim_step0",
         ports=(PortDisplaySpec("out", "right", order=10),),
         order=10,
     )
@@ -71,6 +72,15 @@ class AmesimStep0(AlgebraicComponent):
     def signal_output_values(self, time: float) -> dict[str, float]:
         return {"out": self.output_at(time)}
 
+    def signal_event_times(
+        self,
+        start_time: float,
+        stop_time: float,
+    ) -> tuple[float, ...]:
+        """Expose the exact STEP0 switch time as an integration split point."""
+
+        return (self.time,) if start_time < self.time < stop_time else ()
+
     def component_result_values(self) -> Mapping[str, float]:
         return {"y": self.out.signal}
 
@@ -117,7 +127,7 @@ class AmesimUd00(AlgebraicComponent):
         label="UD00 分段线性信号",
         library_id="amesim",
         category_id="signals",
-        symbol="signal",
+        symbol="amesim_ud00",
         ports=(PortDisplaySpec("out", "right", order=10),),
         order=20,
     )
@@ -200,5 +210,58 @@ class AmesimUd00(AlgebraicComponent):
     def signal_output_values(self, time: float) -> dict[str, float]:
         return {"out": self.output_at(time)}
 
+    def signal_event_times(
+        self,
+        start_time: float,
+        stop_time: float,
+    ) -> tuple[float, ...]:
+        """Return UD00 start, stage, and repeated cycle boundaries.
+
+        The final non-cyclic stage is intentionally not given an end event:
+        ``output_at`` continues that stage's slope after its configured duration.
+        """
+
+        if stop_time <= start_time:
+            return ()
+
+        active_durations = self.durations[: self.nstages]
+        stage_offsets = [0.0]
+        elapsed = 0.0
+        for duration in active_durations[:-1]:
+            elapsed += duration
+            stage_offsets.append(elapsed)
+
+        if not self.iscyclic:
+            return tuple(
+                sorted(
+                    {
+                        event_time
+                        for offset in stage_offsets
+                        if start_time
+                        < (event_time := self.tstart + offset)
+                        < stop_time
+                    }
+                )
+            )
+
+        cycle_duration = sum(active_durations)
+        if cycle_duration <= 0.0:
+            return ()
+
+        events: set[float] = set()
+        for offset in stage_offsets:
+            first_boundary = self.tstart + offset
+            cycle_index = max(
+                0,
+                floor((start_time - first_boundary) / cycle_duration) + 1,
+            )
+            event_time = first_boundary + cycle_index * cycle_duration
+            while event_time < stop_time:
+                if event_time > start_time:
+                    events.add(event_time)
+                cycle_index += 1
+                event_time = first_boundary + cycle_index * cycle_duration
+        return tuple(sorted(events))
+
     def component_result_values(self) -> Mapping[str, float]:
         return {"y": self.out.signal}

app/simulation/components/amesim/storage/chambers.py

@@ -100,7 +100,7 @@ class AmesimPnch023(ThermodynamicVolumeComponent):
         label="PNCH023 固定容积气室",
         library_id="amesim",
         category_id="storage",
-        symbol="tank",
+        symbol="amesim_pnch023",
         ports=(
             PortDisplaySpec("port_1", "left", order=10),
             PortDisplaySpec("port_2", "right", order=20),
@@ -340,7 +340,7 @@ class AmesimPnch012(ThermodynamicVolumeComponent):
         label="PNCH012 变容气室",
         library_id="amesim",
         category_id="storage",
-        symbol="tank",
+        symbol="amesim_pnch012",
         ports=(
             PortDisplaySpec("port_1", "left", order=10),
             PortDisplaySpec("port_2", "right", order=20),

app/simulation/solvers/algebraic.py

@@ -1,7 +1,7 @@
 from __future__ import annotations
 
 from dataclasses import dataclass
-from math import sqrt
+from math import isfinite, sqrt
 
 from app.simulation.core.ports import PortState, VariableRole
 from app.simulation.systems.network import SimulationNetwork
@@ -68,6 +68,7 @@ class PressureFlowSolver:
         self.residual_tolerance = residual_tolerance
         self.max_evaluations = max_evaluations
         self.unknowns = self._build_unknowns()
+        self._unknowns_by_id = {unknown.id: unknown for unknown in self.unknowns}
         self.last_diagnostics: AlgebraicSolveDiagnostics | None = None
 
     def _build_unknowns(self) -> tuple[AlgebraicUnknown, ...]:
@@ -91,48 +92,220 @@ class PressureFlowSolver:
                     )
         return tuple(unknowns)
 
+    @staticmethod
+    def _port_key(variable: str, expected_variable: str) -> tuple[str, str] | None:
+        try:
+            component_name, port_name, variable_name = variable.rsplit(".", 2)
+        except ValueError:
+            return None
+        if variable_name != expected_variable:
+            return None
+        return component_name, port_name
+
     def _seed_equal_pressures(self) -> None:
-        for _ in range(max(2, len(self.network.connections))):
+        """Lift current state pressures across their complete equality groups.
-            changed = False
+
+        Dynamic components refresh their own pressure ports before each closure,
+        while connected algebraic ports retain values from the preceding RHS
+        evaluation.  Merely filling non-positive pressures therefore leaves a
+        stale, and sometimes badly conditioned, nonlinear initial guess.  State
+        equations expose the current pressure as ``port.p - target``; use that
+        target as the authoritative anchor for every connected/equal port.
+        """
+
+        pressure_unknowns = {
+            (unknown.component, unknown.port): unknown
+            for unknown in self.unknowns
+            if unknown.variable == "p"
+        }
+        if not pressure_unknowns:
+            return
+
+        parent = {key: key for key in pressure_unknowns}
+
+        def find(key: tuple[str, str]) -> tuple[str, str]:
+            root = key
+            while parent[root] != root:
+                root = parent[root]
+            while parent[key] != key:
+                next_key = parent[key]
+                parent[key] = root
+                key = next_key
+            return root
+
+        def union(first: tuple[str, str], second: tuple[str, str]) -> None:
+            first_root = find(first)
+            second_root = find(second)
+            if first_root != second_root:
+                parent[second_root] = first_root
+
         for connection in self.network.connections:
             if connection.kind != "physical":
                 continue
-                first = self.network.components[
+            first = connection.endpoint_a.key
-                    connection.endpoint_a.component
+            second = connection.endpoint_b.key
-                ].get_port(connection.endpoint_a.port)
+            if first in pressure_unknowns and second in pressure_unknowns:
-                second = self.network.components[
+                union(first, second)
-                    connection.endpoint_b.component
-                ].get_port(connection.endpoint_b.port)
-                if first.p > 0.0 and second.p <= 0.0:
-                    second.p = first.p
-                    changed = True
-                elif second.p > 0.0 and first.p <= 0.0:
-                    first.p = second.p
-                    changed = True
 
-            for component in self.network.components.values():
+        component_equations = {
-                equal_pressure_equations = [
+            component.name: component.pressure_flow_equation_residuals()
-                    equation
+            for component in self.network.components.values()
-                    for equation in component.pressure_flow_equation_residuals()
+        }
-                    if equation.relation == "equal" and equation.role == "effort"
+        for equations in component_equations.values():
-                ]
+            for equation in equations:
-                for equation in equal_pressure_equations:
+                if equation.relation != "equal" or equation.role != "effort":
-                    states = []
-                    for variable in equation.variables:
-                        _, port_name, variable_name = variable.rsplit(".", 2)
-                        if variable_name == "p":
-                            states.append(component.get_port(port_name))
-                    if len(states) != 2:
                     continue
-                    first, second = states
+                endpoints = [
-                    if first.p > 0.0 and second.p <= 0.0:
+                    endpoint
-                        second.p = first.p
+                    for variable in equation.variables
-                        changed = True
+                    if (
-                    elif second.p > 0.0 and first.p <= 0.0:
+                        (endpoint := self._port_key(variable, "p"))
-                        first.p = second.p
+                        in pressure_unknowns
-                        changed = True
+                    )
-            if not changed:
+                ]
-                break
+                for endpoint in endpoints[1:]:
+                    union(endpoints[0], endpoint)
+
+        members_by_root: dict[tuple[str, str], list[tuple[str, str]]] = {}
+        for endpoint in pressure_unknowns:
+            members_by_root.setdefault(find(endpoint), []).append(endpoint)
+
+        anchors_by_root: dict[tuple[str, str], list[float]] = {}
+        for equations in component_equations.values():
+            for equation in equations:
+                if equation.relation != "state" or equation.role != "effort":
+                    continue
+                endpoints = [
+                    endpoint
+                    for variable in equation.variables
+                    if (
+                        (endpoint := self._port_key(variable, "p"))
+                        in pressure_unknowns
+                    )
+                ]
+                if len(endpoints) != 1:
+                    continue
+                endpoint = endpoints[0]
+                unknown = pressure_unknowns[endpoint]
+                target_pressure = unknown.read() - float(equation.value)
+                if not isfinite(target_pressure):
+                    continue
+                # Keep the state-owned port current even when an invalid model
+                # has conflicting storage anchors in one equality group.
+                unknown.write(target_pressure)
+                anchors_by_root.setdefault(find(endpoint), []).append(target_pressure)
+
+        for root, members in members_by_root.items():
+            anchors = anchors_by_root.get(root, [])
+            if anchors:
+                pressure_scale = max([abs(value) for value in anchors] + [1.0])
+                if max(anchors) - min(anchors) > 1.0e-9 * pressure_scale:
+                    # A conflicting multi-storage group is structurally invalid;
+                    # leave it for the residual solver/preparation diagnostics.
+                    continue
+                target_pressure = sum(anchors) / len(anchors)
+                for endpoint in members:
+                    pressure_unknowns[endpoint].write(target_pressure)
+                continue
+
+            positive_seed = next(
+                (
+                    pressure_unknowns[endpoint].read()
+                    for endpoint in members
+                    if pressure_unknowns[endpoint].read() > 0.0
+                ),
+                None,
+            )
+            if positive_seed is None:
+                continue
+            for endpoint in members:
+                unknown = pressure_unknowns[endpoint]
+                if unknown.read() <= 0.0:
+                    unknown.write(positive_seed)
+
+    def _seed_explicit_mass_flows(self) -> None:
+        """Initialize explicit ``m_flow - f(...)`` constitutive relations.
+
+        AMESim orifices and quasi-steady pneumatic lines expose one mass-flow
+        unknown with unit coefficient.  Once pressure anchors are current, a
+        residual correction places that flow directly on its constitutive
+        surface and avoids asking the nonlinear optimizer to discover the
+        square-root branch from a stale preceding-step value.
+        """
+
+        seeded_ids: set[str] = set()
+        for component in self.network.components.values():
+            for equation in component.pressure_flow_equation_residuals():
+                if equation.relation != "constitutive" or equation.role != "flow":
+                    continue
+                mass_flow_unknowns = [
+                    self._unknowns_by_id[variable]
+                    for variable in equation.variables
+                    if variable in self._unknowns_by_id
+                    and self._unknowns_by_id[variable].variable == "m_flow"
+                ]
+                if len(mass_flow_unknowns) != 1:
+                    continue
+                unknown = mass_flow_unknowns[0]
+                target_flow = unknown.read() - float(equation.value)
+                if not isfinite(target_flow):
+                    continue
+                unknown.write(target_flow)
+                seeded_ids.add(unknown.id)
+
+        # Complete local two-port balances for explicit elements. Connection
+        # flow equations remain available to align the adjacent component port.
+        for component in self.network.components.values():
+            for equation in component.pressure_flow_equation_residuals():
+                if equation.relation != "sumToZero" or equation.role != "flow":
+                    continue
+                mass_flow_unknowns = [
+                    self._unknowns_by_id[variable]
+                    for variable in equation.variables
+                    if variable in self._unknowns_by_id
+                    and self._unknowns_by_id[variable].variable == "m_flow"
+                ]
+                if len(mass_flow_unknowns) != 2:
+                    continue
+                seeded = [
+                    unknown for unknown in mass_flow_unknowns if unknown.id in seeded_ids
+                ]
+                if len(seeded) != 1:
+                    continue
+                other = next(
+                    unknown for unknown in mass_flow_unknowns if unknown.id not in seeded_ids
+                )
+                other.write(-seeded[0].read())
+                seeded_ids.add(other.id)
+
+        # A physical connector imposes the same sum-to-zero flow rule as a
+        # two-port component.  Once an explicit component flow is known, carry
+        # that guess to the connected storage/boundary port as well.  For the
+        # common volume-orifice-volume topology this makes the seeded state an
+        # exact algebraic solution and avoids an unnecessary nonlinear solve on
+        # every ODE/Jacobian evaluation.
+        for connection in self.network.connections:
+            if connection.kind != "physical":
+                continue
+            endpoint_unknowns = []
+            for endpoint in connection.endpoints:
+                unknown = self._unknowns_by_id.get(
+                    f"{endpoint.component}.{endpoint.port}.m_flow"
+                )
+                if unknown is not None:
+                    endpoint_unknowns.append(unknown)
+            if len(endpoint_unknowns) != 2:
+                continue
+            seeded = [
+                unknown for unknown in endpoint_unknowns if unknown.id in seeded_ids
+            ]
+            if len(seeded) != 1:
+                continue
+            other = next(
+                unknown for unknown in endpoint_unknowns if unknown.id not in seeded_ids
+            )
+            other.write(-seeded[0].read())
+            seeded_ids.add(other.id)
 
     def _scales(self) -> dict[str, float]:
         pressure_scale = max(
@@ -184,6 +357,7 @@ class PressureFlowSolver:
             ) from exc
 
         self._seed_equal_pressures()
+        self._seed_explicit_mass_flows()
         scales = self._scales()
         pressure_scale = scales["p"]
         flow_scale = scales["m_flow"]
@@ -216,6 +390,40 @@ class PressureFlowSolver:
                 return pressure_scale
             return max([scales.get(name, 1.0) for name in variable_names] + [1.0])
 
+        seeded_equations = self.network.pressure_flow_equation_residuals()
+        seeded_scaled = [
+            abs(equation.value / equation_scale(equation))
+            for equation in seeded_equations
+        ]
+        seeded_max_scaled_residual = max(seeded_scaled, default=0.0)
+        seeded_unknown_values = [
+            (unknown, unknown.read()) for unknown in self.unknowns
+        ]
+        seeded_unknowns_are_feasible = all(
+            isfinite(value)
+            and (unknown.variable != "p" or value >= 1.0)
+            for unknown, value in seeded_unknown_values
+        )
+        if (
+            seeded_unknowns_are_feasible
+            and all(isfinite(value) for value in seeded_scaled)
+            and seeded_max_scaled_residual <= self.residual_tolerance
+        ):
+            diagnostics = AlgebraicSolveDiagnostics(
+                success=True,
+                message="Seeded pressure-flow state satisfies the residual tolerance.",
+                evaluations=0,
+                pressure_scale=pressure_scale,
+                flow_scale=flow_scale,
+                max_scaled_residual=seeded_max_scaled_residual,
+                max_raw_residual=max(
+                    (abs(item.value) for item in seeded_equations),
+                    default=0.0,
+                ),
+            )
+            self.last_diagnostics = diagnostics
+            return diagnostics
+
         x0 = np.asarray(
             [
                 (
@@ -269,14 +477,20 @@ class PressureFlowSolver:
             )
             for equation in equations
         ]
-        success = bool(result.success) and max(scaled, default=0.0) <= self.residual_tolerance
+        max_scaled_residual = max(scaled, default=0.0)
+        residuals_converged = (
+            all(isfinite(value) for value in scaled)
+            and max_scaled_residual <= self.residual_tolerance
+        )
+        optimizer_status_is_acceptable = bool(result.success) or int(result.status) == 0
+        success = residuals_converged and optimizer_status_is_acceptable
         diagnostics = AlgebraicSolveDiagnostics(
             success=success,
             message=str(result.message),
             evaluations=int(result.nfev),
             pressure_scale=pressure_scale,
             flow_scale=flow_scale,
-            max_scaled_residual=max(scaled, default=0.0),
+            max_scaled_residual=max_scaled_residual,
             max_raw_residual=max((abs(item.value) for item in equations), default=0.0),
         )
         self.last_diagnostics = diagnostics

app/simulation/solvers/signal.py

@@ -1,6 +1,7 @@
 from __future__ import annotations
 
 from dataclasses import dataclass
+from math import isfinite
 from typing import Protocol
 
 from app.simulation.systems.network import Endpoint, SimulationNetwork
@@ -13,6 +14,21 @@ class SignalOutputComponent(Protocol):
         ...
 
 
+class SignalEventSource(Protocol):
+    """Optional contract for signal sources with known time discontinuities."""
+
+    name: str
+
+    def signal_event_times(
+        self,
+        start_time: float,
+        stop_time: float,
+    ) -> tuple[float, ...]:
+        """Return event times strictly inside ``(start_time, stop_time)``."""
+
+        ...
+
+
 @dataclass(frozen=True)
 class SignalSolveDiagnostics:
     propagated: int
@@ -51,6 +67,37 @@ class SignalResolver:
         self.last_diagnostics = diagnostics
         return diagnostics
 
+    def event_times(self, start_time: float, stop_time: float) -> tuple[float, ...]:
+        """Collect optional source events that can be used as integration splits.
+
+        Event discovery is deliberately duck typed so existing signal-output
+        components remain valid without implementing ``signal_event_times``.
+        """
+
+        start = float(start_time)
+        stop = float(stop_time)
+        if not isfinite(start) or not isfinite(stop):
+            raise ValueError("Signal event interval must be finite.")
+        if stop < start:
+            raise ValueError("Signal event interval stop must not precede start.")
+        if stop == start:
+            return ()
+
+        events: set[float] = set()
+        for component in self.network.components.values():
+            source_event_times = getattr(component, "signal_event_times", None)
+            if source_event_times is None:
+                continue
+            for raw_time in source_event_times(start, stop):
+                event_time = float(raw_time)
+                if not isfinite(event_time):
+                    raise ValueError(
+                        f"Signal event time from component '{component.name}' must be finite."
+                    )
+                if start < event_time < stop:
+                    events.add(event_time)
+        return tuple(sorted(events))
+
     def _source_target(self, endpoints: tuple[Endpoint, Endpoint]) -> tuple[Endpoint, Endpoint]:
         first, second = endpoints
         first_port = self.network.components[first.component].get_port(first.port)

app/simulation/solvers/solver.py

@@ -1,7 +1,8 @@
 from __future__ import annotations
 
+import math
 from dataclasses import dataclass
-from typing import Callable, Literal
+from typing import Callable, Literal, Sequence
 
 
 CancellationCheck = Callable[[], bool]
@@ -51,6 +52,33 @@ def _append_solution_sample(
         states[index].append(float(value))
 
 
+def _normalize_breakpoints(
+    config: SolveIVPConfig,
+    breakpoints: Sequence[float] | None,
+) -> list[float]:
+    """Return sorted, unique breakpoints strictly inside the integration span."""
+
+    if breakpoints is None or len(breakpoints) == 0:
+        return []
+    if config.t_stop < config.t_start:
+        raise ValueError("Segmented integration requires t_stop to follow t_start.")
+
+    normalized: list[float] = []
+    for raw_breakpoint in breakpoints:
+        breakpoint = float(raw_breakpoint)
+        if not math.isfinite(breakpoint):
+            raise ValueError("Integration breakpoints must be finite numbers.")
+        if config.t_start < breakpoint < config.t_stop:
+            normalized.append(breakpoint)
+
+    normalized.sort()
+    return [
+        breakpoint
+        for index, breakpoint in enumerate(normalized)
+        if index == 0 or breakpoint != normalized[index - 1]
+    ]
+
+
 def _runge_kutta_4(
     rhs: Callable[[float, list[float]], list[float]],
     initial_state: list[float],
@@ -114,6 +142,137 @@ def _runge_kutta_4(
     )
 
 
+def _runge_kutta_4_segmented(
+    rhs: Callable[[float, list[float]], list[float]],
+    initial_state: list[float],
+    config: SolveIVPConfig,
+    t_eval: list[float] | None,
+    breakpoints: Sequence[float],
+    cancel_check: CancellationCheck | None = None,
+    accepted_step_callback: AcceptedStepCallback | None = None,
+) -> ODESolution:
+    """RK4 fallback that never evaluates a pre-breakpoint step at the breakpoint."""
+
+    if t_eval is None:
+        point_count = max(
+            2,
+            int((config.t_stop - config.t_start) / max(config.max_step, 1e-6)) + 1,
+        )
+        sample_step = (config.t_stop - config.t_start) / (point_count - 1)
+        sample_times = [
+            config.t_start + index * sample_step for index in range(point_count)
+        ]
+    else:
+        sample_times = [float(time) for time in t_eval]
+
+    state = [float(value) for value in initial_state]
+    states = [[value] for value in state]
+    times = [float(config.t_start)]
+    current_time = float(config.t_start)
+    sample_index = 0
+    while (
+        sample_index < len(sample_times)
+        and sample_times[sample_index] <= config.t_start + 1e-12
+    ):
+        sample_index += 1
+
+    status: IntegrationStatus = "completed"
+    message = "Integrated with built-in RK4 fallback because SciPy is unavailable."
+    error: Exception | None = None
+    last_reported_step: float | None = None
+
+    def report_step(time: float) -> None:
+        nonlocal last_reported_step
+        if accepted_step_callback is None:
+            return
+        if last_reported_step is not None and time <= last_reported_step:
+            return
+        accepted_step_callback(float(time))
+        last_reported_step = float(time)
+
+    def advance_to(
+        target_time: float, reported_terminal_time: float | None = None
+    ) -> None:
+        nonlocal current_time, state
+        while current_time < target_time - 1e-15:
+            if cancel_check is not None and cancel_check():
+                raise _IntegrationCancelled
+            dt = min(config.max_step, target_time - current_time)
+            k1 = rhs(current_time, state)
+            k2 = rhs(
+                current_time + 0.5 * dt,
+                _vector_add(state, k1, 0.5 * dt),
+            )
+            k3 = rhs(
+                current_time + 0.5 * dt,
+                _vector_add(state, k2, 0.5 * dt),
+            )
+            k4 = rhs(current_time + dt, _vector_add(state, k3, dt))
+            state = [
+                value + (dt / 6.0) * (a + 2.0 * b + 2.0 * c + d)
+                for value, a, b, c, d in zip(state, k1, k2, k3, k4)
+            ]
+            current_time += dt
+            report_time = current_time
+            if (
+                reported_terminal_time is not None
+                and current_time >= target_time - 1e-15
+            ):
+                report_time = reported_terminal_time
+            report_step(report_time)
+
+    try:
+        segment_ends = [*breakpoints, float(config.t_stop)]
+        for segment_index, segment_end in enumerate(segment_ends):
+            is_breakpoint = segment_index < len(breakpoints)
+            integration_end = (
+                math.nextafter(segment_end, -math.inf) if is_breakpoint else segment_end
+            )
+
+            while (
+                sample_index < len(sample_times)
+                and sample_times[sample_index] <= integration_end
+            ):
+                sample_time = float(sample_times[sample_index])
+                advance_to(sample_time)
+                _append_solution_sample(times, states, sample_time, state)
+                sample_index += 1
+
+            advance_to(
+                integration_end,
+                segment_end if is_breakpoint else None,
+            )
+
+            if is_breakpoint:
+                current_time = float(segment_end)
+                report_step(current_time)
+                while (
+                    sample_index < len(sample_times)
+                    and sample_times[sample_index] <= segment_end
+                ):
+                    sample_time = float(sample_times[sample_index])
+                    _append_solution_sample(times, states, sample_time, state)
+                    sample_index += 1
+    except _IntegrationCancelled:
+        status = "cancelled"
+        message = "Simulation was stopped before reaching the requested end time."
+        _append_solution_sample(times, states, current_time, state)
+    except Exception as exc:
+        status = "failed"
+        message = str(exc)
+        error = exc
+        _append_solution_sample(times, states, current_time, state)
+
+    return ODESolution(
+        t=times,
+        y=states,
+        success=status == "completed",
+        message=message,
+        status=status,
+        error=error,
+    )
+
+
 def _integrate_scipy_stepwise(
     rhs: Callable[[float, list[float]], list[float]],
     initial_state: list[float],
@@ -121,6 +280,7 @@ def _integrate_scipy_stepwise(
     t_eval: list[float] | None,
     cancel_check: CancellationCheck,
     accepted_step_callback: AcceptedStepCallback | None,
+    breakpoints: Sequence[float] = (),
 ) -> ODESolution:
     import numpy as np
     from scipy.integrate import BDF, DOP853, LSODA, RK23, RK45, Radau
@@ -141,7 +301,7 @@ def _integrate_scipy_stepwise(
     states = [[float(value)] for value in initial_state]
     last_accepted_time = float(config.t_start)
     last_accepted_state = [float(value) for value in initial_state]
-    sample_times = list(t_eval or [])
+    sample_times = [float(time) for time in (t_eval or [])]
     sample_index = 0
     while (
         sample_index < len(sample_times)
@@ -154,63 +314,85 @@ def _integrate_scipy_stepwise(
             raise _IntegrationCancelled
         return rhs(float(time), [float(value) for value in state])
 
-    if cancel_check():
+    status: IntegrationStatus = "completed"
-        return ODESolution(
+    message = "The solver successfully reached the end of the integration interval."
-            t=times,
+    error: Exception | None = None
-            y=states,
+    last_reported_step: float | None = None
-            success=False,
-            message="Simulation was stopped before integration started.",
-            status="cancelled",
-        )
 
+    def report_step(time: float) -> None:
+        nonlocal last_reported_step
+        if accepted_step_callback is None:
+            return
+        if last_reported_step is not None and time <= last_reported_step:
+            return
+        accepted_step_callback(float(time))
+        last_reported_step = float(time)
+
+    segment_ends = [*breakpoints, float(config.t_stop)]
+    for segment_index, segment_end in enumerate(segment_ends):
+        if cancel_check():
+            status = "cancelled"
+            message = (
+                "Simulation was stopped before integration started."
+                if segment_index == 0
+                else "Simulation was stopped before reaching the requested end time."
+            )
+            break
+
+        is_breakpoint = segment_index < len(breakpoints)
+        integration_end = (
+            math.nextafter(segment_end, -math.inf) if is_breakpoint else segment_end
+        )
+        has_integration_interval = integration_end > last_accepted_time
+
+        if has_integration_interval:
             solver_options = {
                 "rtol": config.rtol,
                 "atol": config.atol,
                 "max_step": config.max_step,
             }
             if config.first_step is not None:
-        solver_options["first_step"] = config.first_step
+                solver_options["first_step"] = min(
+                    config.first_step,
+                    integration_end - last_accepted_time,
+                )
 
             try:
                 solver = solver_type(
                     cancellable_rhs,
-            config.t_start,
+                    last_accepted_time,
-            np.asarray(initial_state, dtype=float),
+                    np.asarray(last_accepted_state, dtype=float),
-            config.t_stop,
+                    integration_end,
                     **solver_options,
                 )
             except _IntegrationCancelled:
-        return ODESolution(
+                status = "cancelled"
-            t=times,
+                message = (
-            y=states,
+                    "Simulation was stopped before integration started."
-            success=False,
+                    if segment_index == 0
-            message="Simulation was stopped before integration started.",
+                    else "Simulation was stopped before reaching the requested end time."
-            status="cancelled",
                 )
+                break
             except Exception as exc:
-        return ODESolution(
+                status = "failed"
-            t=times,
+                message = str(exc)
-            y=states,
+                error = exc
-            success=False,
+                break
-            message=str(exc),
-            status="failed",
-            error=exc,
-        )
-
-    status: IntegrationStatus = "completed"
-    message = "The solver successfully reached the end of the integration interval."
-    error: Exception | None = None
 
             while solver.status == "running":
                 if cancel_check():
                     status = "cancelled"
-            message = "Simulation was stopped before reaching the requested end time."
+                    message = (
+                        "Simulation was stopped before reaching the requested end time."
+                    )
                     break
                 try:
                     step_message = solver.step()
                 except _IntegrationCancelled:
                     status = "cancelled"
-            message = "Simulation was stopped before reaching the requested end time."
+                    message = (
+                        "Simulation was stopped before reaching the requested end time."
+                    )
                     break
                 except Exception as exc:
                     status = "failed"
@@ -225,25 +407,67 @@ def _integrate_scipy_stepwise(
 
                 last_accepted_time = float(solver.t)
                 last_accepted_state = [float(value) for value in solver.y]
+                reported_time = (
+                    float(segment_end)
+                    if is_breakpoint and solver.status == "finished"
+                    else last_accepted_time
+                )
                 if sample_times:
                     dense_output = solver.dense_output()
                     while (
                         sample_index < len(sample_times)
-                and sample_times[sample_index] <= last_accepted_time + 1e-12
+                        and sample_times[sample_index] <= last_accepted_time
                     ):
                         sample_time = float(sample_times[sample_index])
-                sample_state = [float(value) for value in dense_output(sample_time)]
+                        sample_state = [
-                _append_solution_sample(times, states, sample_time, sample_state)
+                            float(value) for value in dense_output(sample_time)
+                        ]
+                        _append_solution_sample(
+                            times,
+                            states,
+                            sample_time,
+                            sample_state,
+                        )
                         sample_index += 1
                 else:
+                    _append_solution_sample(
+                        times,
+                        states,
+                        reported_time,
+                        last_accepted_state,
+                    )
+                report_step(reported_time)
+
+            if status != "completed":
+                break
+
+        if is_breakpoint:
+            # The old equation is integrated only to the representable point just
+            # left of the event.  The continuous state is then lifted to the exact
+            # event time, where the freshly constructed next solver sees the new
+            # equation immediately.
+            last_accepted_time = float(segment_end)
+            if sample_times:
+                while (
+                    sample_index < len(sample_times)
+                    and sample_times[sample_index] <= segment_end
+                ):
+                    sample_time = float(sample_times[sample_index])
+                    _append_solution_sample(
+                        times,
+                        states,
+                        sample_time,
+                        last_accepted_state,
+                    )
+                    sample_index += 1
+            elif not has_integration_interval:
                 _append_solution_sample(
                     times,
                     states,
                     last_accepted_time,
                     last_accepted_state,
                 )
-        if accepted_step_callback is not None:
+            report_step(last_accepted_time)
-            accepted_step_callback(last_accepted_time)
 
     if status != "completed":
         _append_solution_sample(
@@ -270,8 +494,14 @@ def integrate_ode(
     t_eval: list[float] | None = None,
     cancel_check: CancellationCheck | None = None,
     accepted_step_callback: AcceptedStepCallback | None = None,
+    breakpoints: Sequence[float] | None = None,
 ):
-    """Thin wrapper around scipy.integrate.solve_ivp with a pure-Python fallback."""
+    """Integrate an ODE, optionally restarting at equation discontinuities.
+
+    Breakpoints are interpreted as right-continuous equation changes: the old
+    equation is integrated to the floating-point left limit, then a fresh solver
+    starts at the exact breakpoint with the unchanged continuous state.
+    """
 
     if abs(config.t_stop - config.t_start) <= 1e-15:
         return ODESolution(
@@ -281,9 +511,21 @@ def integrate_ode(
             message="Skipped integration because t_start equals t_stop.",
         )
 
+    normalized_breakpoints = _normalize_breakpoints(config, breakpoints)
+
     try:
         from scipy.integrate import solve_ivp
     except ImportError:
+        if normalized_breakpoints:
+            return _runge_kutta_4_segmented(
+                rhs,
+                initial_state,
+                config,
+                t_eval,
+                normalized_breakpoints,
+                cancel_check,
+                accepted_step_callback,
+            )
         return _runge_kutta_4(
             rhs,
             initial_state,
@@ -293,14 +535,15 @@ def integrate_ode(
             accepted_step_callback,
         )
 
-    if cancel_check is not None:
+    if cancel_check is not None or normalized_breakpoints:
         return _integrate_scipy_stepwise(
             rhs,
             initial_state,
             config,
             t_eval,
-            cancel_check,
+            cancel_check or (lambda: False),
             accepted_step_callback,
+            normalized_breakpoints,
         )
 
     solve_options = {

app/simulation/systems/generic.py

@@ -327,6 +327,10 @@ class GenericFluidSystem:
 
         report_progress(0.0, "initializing", force=True)
         t_eval = simulation_sample_times(config, sample_step)
+        signal_event_times = self.signal_resolver.event_times(
+            config.t_start,
+            config.t_stop,
+        )
         initial_state = self.consistent_initial_state_vector()
         report_progress(0.0, "integrating", force=True)
         duration = config.t_stop - config.t_start
@@ -356,6 +360,7 @@ class GenericFluidSystem:
             accepted_step_callback=(
                 report_solver_time if cancel_check is not None else None
             ),
+            breakpoints=signal_event_times,
         )
         if isinstance(solution, ODESolution):
             run_status: SimulationRunStatus = solution.status
@@ -428,6 +433,7 @@ class GenericFluidSystem:
             },
             "signal": {
                 "propagations": self.signal_propagation_count,
+                "eventTimes": list(signal_event_times),
                 "last": (
                     self.signal_resolver.last_diagnostics.as_dict()
                     if self.signal_resolver.last_diagnostics is not None

frontend/src/App.tsx

@@ -89,6 +89,10 @@ import {
   type ParameterColumnLayout,
   type ParameterTableRow,
 } from "./ParameterTable";
+import {
+  evaluateParameterExpression,
+  isParameterExpressionValue,
+} from "./parameterExpression";
 import {
   WorkspaceViewTabs,
   type WorkspaceView,
@@ -219,7 +223,17 @@ type SimulationNodeData = {
 type SimulationNode = Node<SimulationNodeData, "simulationComponent">;
 type SimulationEdge = Edge;
 
+type SimulationNumericKey = "t_start" | "t_stop" | "step" | "max_step";
+
 type SimulationConfig = {
+  t_start: ParameterValue;
+  t_stop: ParameterValue;
+  step: ParameterValue;
+  max_step: ParameterValue;
+  method: string;
+};
+
+type ResolvedSimulationConfig = {
   t_start: number;
   t_stop: number;
   step: number;
@@ -255,6 +269,10 @@ type ReactFlowProjectPayload = {
   simulation: SimulationConfig;
 };
 
+type ExecutableProjectPayload = Omit<ReactFlowProjectPayload, "simulation"> & {
+  simulation: ResolvedSimulationConfig;
+};
+
 type SimulationResult = {
   success: boolean;
   status: "completed" | "stopped" | "stalled" | "failed";
@@ -534,7 +552,7 @@ const unitOptions: Record<UnitQuantity, UnitOption[]> = {
   ],
 };
 
-const defaultSimulationConfig: SimulationConfig = {
+const defaultSimulationConfig: ResolvedSimulationConfig = {
   t_start: 0,
   t_stop: 2,
   step: 0.1,
@@ -625,6 +643,12 @@ type SimulationStreamEvent =
       totalTime?: number;
     };
 const SUPPORTED_SOLVER_METHODS = ["BDF", "Radau", "LSODA", "RK45", "RK23", "DOP853"];
+const simulationConfigLabels: Record<SimulationNumericKey, string> = {
+  t_start: "起始时间",
+  t_stop: "结束时间",
+  step: "采样步长",
+  max_step: "最大积分步长",
+};
 
 function physicalPort(
   name: string,
@@ -1527,7 +1551,7 @@ type NormalizedSimulationProgress = {
 
 function normalizeSimulationProgressEvent(
   event: Extract<SimulationStreamEvent, { event: "progress" }>,
-  config: SimulationConfig,
+  config: ResolvedSimulationConfig,
 ): NormalizedSimulationProgress {
   const totalTime = Number.isFinite(event.totalTime)
     ? Number(event.totalTime)
@@ -2184,7 +2208,7 @@ function DeferredNumberInput({
     <input
       aria-invalid={invalid}
       aria-label={ariaLabel}
-      inputMode="decimal"
+      inputMode="text"
       onBlur={() => {
         editingRef.current = false;
         if (cancelCommitRef.current) {
@@ -3013,10 +3037,11 @@ function FlowWorkbench() {
     const selectedUnit =
       selectedNode?.data.parameterUnits[key] ?? definition.unit ?? "";
     const unit = findUnitOption(definition, selectedUnit);
-    const numericValue = Number(displayValue);
+    const normalizedDisplayValue = displayValue.trim();
+    const numericValue = Number(normalizedDisplayValue);
     const baseValue =
-      displayValue.trim() === "" || !Number.isFinite(numericValue)
+      normalizedDisplayValue === "" || !Number.isFinite(numericValue)
-        ? displayValue
+        ? normalizedDisplayValue
         : unit.toBase(numericValue);
 
     updateSelectedNode((node) => ({
@@ -3216,15 +3241,22 @@ function FlowWorkbench() {
   ]);
 
   const updateSimulationConfig = (key: keyof SimulationConfig, value: string) => {
+    const normalizedValue = value.trim();
+    const numericValue = Number(normalizedValue);
     setSimulationConfig((current) => ({
       ...current,
-      [key]: key === "method" ? value : Number(value),
+      [key]:
+        key === "method"
+          ? value
+          : normalizedValue !== "" && Number.isFinite(numericValue)
+            ? numericValue
+            : normalizedValue,
     }));
   };
 
   const generateXml = () => {
     try {
-      const xml = buildSystemXml(buildCurrentProject());
+      const xml = buildSystemXml(buildCurrentProject(), componentDefinitions);
       changeConsoleMode("normal");
       appendConsoleEntry(
         "success",
@@ -3239,7 +3271,7 @@ function FlowWorkbench() {
 
   const downloadXml = () => {
     try {
-      const xml = buildSystemXml(buildCurrentProject());
+      const xml = buildSystemXml(buildCurrentProject(), componentDefinitions);
       downloadText(`${safeFilename(projectName)}.xml`, xml);
       appendConsoleEntry("success", `XML 已下载：${safeFilename(projectName)}.xml`);
     } catch (error) {
@@ -3402,7 +3434,7 @@ function FlowWorkbench() {
 
   const publishSimulationResult = (
     result: SimulationResult,
-    project: ReactFlowProjectPayload,
+    project: ExecutableProjectPayload,
   ) => {
     const resultStatus = result.status ?? (result.success ? "completed" : "failed");
     const sampleCount = Math.min(
@@ -3510,34 +3542,48 @@ function FlowWorkbench() {
   const runSimulation = async () => {
     const issues = checkModel();
     const modelErrors = issues.filter((issue) => issue.severity === "error");
+    const simulationResolution = resolveSimulationConfig(
+      simulationConfigRef.current,
+    );
+    const progressConfig = simulationResolution.ok
+      ? simulationResolution.value
+      : defaultSimulationConfig;
     if (modelErrors.length > 0) {
       changeConsoleMode("normal");
       setSimulationProgress({
         state: "error",
         percent: 0,
         message: "模型检查未通过",
-        startTime: simulationConfigRef.current.t_start,
+        startTime: progressConfig.t_start,
-        simulatedTime: simulationConfigRef.current.t_start,
+        simulatedTime: progressConfig.t_start,
-        totalTime: simulationConfigRef.current.t_stop,
+        totalTime: progressConfig.t_stop,
       });
       return;
     }
+    if (!simulationResolution.ok) {
+      changeConsoleMode("normal");
+      appendConsoleEntry("error", simulationResolution.message);
+      return;
+    }
+    const project: ExecutableProjectPayload = {
+      ...buildCurrentProject(),
+      simulation: simulationResolution.value,
+    };
     changeConsoleMode("normal");
     setSimulationProgress({
       state: "running",
       percent: 0,
       message: "正在提交仿真任务",
-      startTime: simulationConfigRef.current.t_start,
+      startTime: project.simulation.t_start,
-      simulatedTime: simulationConfigRef.current.t_start,
+      simulatedTime: project.simulation.t_start,
-      totalTime: simulationConfigRef.current.t_stop,
+      totalTime: project.simulation.t_stop,
     });
     appendConsoleEntry(
       "info",
-      `开始仿真：${projectNameRef.current || "untitled"}，时间范围 ${simulationConfigRef.current.t_start} - ${simulationConfigRef.current.t_stop} s`,
+      `开始仿真：${projectNameRef.current || "untitled"}，时间范围 ${project.simulation.t_start} - ${project.simulation.t_stop} s`,
     );
     await runBusyAction("正在编译模型并运行仿真...", async () => {
-      const project = buildCurrentProject();
+      const xml = buildSystemXml(project, componentDefinitions);
-      const xml = buildSystemXml(project);
       const simulationId = createSimulationId();
       activeSimulationIdRef.current = simulationId;
       setSimulationStopPending(false);
@@ -3988,7 +4034,11 @@ function FlowWorkbench() {
               const error =
                 gasReference && !gasReferenceAvailable
                   ? "引用的介质定义不存在"
-                  : parameterValidationMessage(definition, baseValue);
+                  : parameterValidationMessage(
+                      definition,
+                      baseValue,
+                      selectedUnit,
+                    );
               let valueControl: ReactNode;
               if (mediumDefinitionIndex) {
                 valueControl = (
@@ -4103,12 +4153,20 @@ function FlowWorkbench() {
                   definition,
                   selectedUnit,
                 ),
+                calculatedValue: parameterCalculatedValueMetadata(
+                  baseValue,
+                  definition,
+                  selectedUnit,
+                ),
               };
             },
           ),
         ]
       : [];
 
+  const simulationSettingErrors = simulationConfigValidationMessages(
+    simulationConfig,
+  );
   const simulationSettingRows: ParameterTableRow[] = [
     {
       id: "simulation-t-start",
@@ -4116,6 +4174,7 @@ function FlowWorkbench() {
       value: (
         <DeferredNumberInput
           ariaLabel="起始时间"
+          invalid={Boolean(simulationSettingErrors.t_start)}
           value={simulationConfig.t_start}
           onCommit={(value) => updateSimulationConfig("t_start", value)}
           onEditEnd={finishHistoryEdit}
@@ -4127,6 +4186,11 @@ function FlowWorkbench() {
       defaultValue: `${defaultSimulationConfig.t_start} s`,
       range: "有限数值",
       currentUnit: "s",
+      error: simulationSettingErrors.t_start,
+      calculatedValue: simulationCalculatedValueMetadata(
+        simulationConfig.t_start,
+        "s",
+      ),
     },
     {
       id: "simulation-t-stop",
@@ -4134,6 +4198,7 @@ function FlowWorkbench() {
       value: (
         <DeferredNumberInput
           ariaLabel="结束时间"
+          invalid={Boolean(simulationSettingErrors.t_stop)}
           value={simulationConfig.t_stop}
           onCommit={(value) => updateSimulationConfig("t_stop", value)}
           onEditEnd={finishHistoryEdit}
@@ -4145,6 +4210,11 @@ function FlowWorkbench() {
       defaultValue: `${defaultSimulationConfig.t_stop} s`,
       range: "> 起始时间",
       currentUnit: "s",
+      error: simulationSettingErrors.t_stop,
+      calculatedValue: simulationCalculatedValueMetadata(
+        simulationConfig.t_stop,
+        "s",
+      ),
     },
     {
       id: "simulation-step",
@@ -4152,6 +4222,7 @@ function FlowWorkbench() {
       value: (
         <DeferredNumberInput
           ariaLabel="采样步长"
+          invalid={Boolean(simulationSettingErrors.step)}
           value={simulationConfig.step}
           onCommit={(value) => updateSimulationConfig("step", value)}
           onEditEnd={finishHistoryEdit}
@@ -4163,6 +4234,11 @@ function FlowWorkbench() {
       defaultValue: `${defaultSimulationConfig.step} s`,
       range: "> 0",
       currentUnit: "s",
+      error: simulationSettingErrors.step,
+      calculatedValue: simulationCalculatedValueMetadata(
+        simulationConfig.step,
+        "s",
+      ),
     },
     {
       id: "simulation-max-step",
@@ -4170,6 +4246,7 @@ function FlowWorkbench() {
       value: (
         <DeferredNumberInput
           ariaLabel="最大积分步长"
+          invalid={Boolean(simulationSettingErrors.max_step)}
           value={simulationConfig.max_step}
           onCommit={(value) => updateSimulationConfig("max_step", value)}
           onEditEnd={finishHistoryEdit}
@@ -4181,6 +4258,11 @@ function FlowWorkbench() {
       defaultValue: `${defaultSimulationConfig.max_step} s`,
       range: "> 0",
       currentUnit: "s",
+      error: simulationSettingErrors.max_step,
+      calculatedValue: simulationCalculatedValueMetadata(
+        simulationConfig.max_step,
+        "s",
+      ),
     },
     {
       id: "simulation-method",
@@ -4838,7 +4920,9 @@ function normalizeLoadedNode(
       label: node.data.label || definition?.label || node.id,
       componentType: node.data.componentType || definition?.type || "component",
       modelType: node.data.modelType || definition?.modelType || node.data.componentType,
-      symbol: node.data.symbol || definition?.symbol || node.data.componentType,
+      // Catalog symbols are versioned presentation metadata. Prefer the current
+      // definition so projects saved with an old generic icon are upgraded on load.
+      symbol: definition?.symbol || node.data.symbol || node.data.componentType,
       ports: normalizeLoadedPorts(node.data.ports, definition),
       parameters,
       parameterUnits,
@@ -5122,17 +5206,95 @@ function parameterCurrentUnitMetadata(
     : undefined;
 }
 
+type NumericInputResolution =
+  | { ok: true; value: number; expression: boolean }
+  | { ok: false; message: string; expression: boolean };
+
+function resolveNumericInput(value: ParameterValue): NumericInputResolution {
+  if (typeof value === "number") {
+    return Number.isFinite(value)
+      ? { ok: true, value, expression: false }
+      : { ok: false, message: "请输入有限数值", expression: false };
+  }
+
+  const normalizedValue = value.trim();
+  if (!normalizedValue) {
+    return { ok: false, message: "参数不能为空", expression: false };
+  }
+  const numericValue = Number(normalizedValue);
+  if (Number.isFinite(numericValue)) {
+    return { ok: true, value: numericValue, expression: false };
+  }
+
+  const evaluated = evaluateParameterExpression(normalizedValue);
+  return evaluated.ok
+    ? { ok: true, value: evaluated.value, expression: true }
+    : {
+        ok: false,
+        message: `等式无法计算：${evaluated.message}`,
+        expression: true,
+      };
+}
+
+function resolveParameterValue(
+  value: ParameterValue,
+  definition: ParameterDefinition,
+  selectedUnit: string,
+): NumericInputResolution {
+  const resolved = resolveNumericInput(value);
+  if (!resolved.ok) {
+    return resolved;
+  }
+  if (resolved.expression && definition.editor) {
+    return {
+      ok: false,
+      message: "该离散参数只能通过下拉栏选择",
+      expression: true,
+    };
+  }
+  if (!resolved.expression) {
+    return resolved;
+  }
+
+  const baseValue = findUnitOption(definition, selectedUnit).toBase(
+    resolved.value,
+  );
+  return Number.isFinite(baseValue)
+    ? { ...resolved, value: baseValue }
+    : {
+        ok: false,
+        message: "等式换算到基础单位后不是有限数值",
+        expression: true,
+      };
+}
+
+function parameterCalculatedValueMetadata(
+  value: ParameterValue,
+  definition: ParameterDefinition,
+  selectedUnit: string,
+) {
+  if (!isParameterExpressionValue(value)) {
+    return undefined;
+  }
+  const resolved = resolveParameterValue(value, definition, selectedUnit);
+  if (!resolved.ok || !resolved.expression) {
+    return undefined;
+  }
+  const unit = findUnitOption(definition, selectedUnit);
+  const displayValue = unit.fromBase(resolved.value);
+  return `${formatEditableNumber(displayValue)}${unit.label ? ` ${unit.label}` : ""}`;
+}
+
 function parameterValidationMessage(
   definition: ParameterDefinition,
   value: ParameterValue,
+  selectedUnit: string,
 ) {
-  if (typeof value === "string" && value.trim() === "") {
+  const resolved = resolveParameterValue(value, definition, selectedUnit);
-    return "参数不能为空";
+  if (!resolved.ok) {
-  }
+    return resolved.message;
-  const numericValue = Number(value);
-  if (!Number.isFinite(numericValue)) {
-    return "请输入有效数字";
   }
+  const numericValue = resolved.value;
   if (
     definition.options &&
     !definition.options.some((option) => option.value === numericValue)
@@ -5153,6 +5315,85 @@ function parameterValidationMessage(
   return "";
 }
 
+function simulationCalculatedValueMetadata(
+  value: ParameterValue,
+  unit: string,
+) {
+  if (!isParameterExpressionValue(value)) {
+    return undefined;
+  }
+  const resolved = resolveNumericInput(value);
+  if (!resolved.ok || !resolved.expression) {
+    return undefined;
+  }
+  return `${formatEditableNumber(resolved.value)}${unit ? ` ${unit}` : ""}`;
+}
+
+function simulationConfigValidationMessages(
+  simulation: SimulationConfig,
+): Partial<Record<SimulationNumericKey, string>> {
+  const resolutions = {
+    t_start: resolveNumericInput(simulation.t_start),
+    t_stop: resolveNumericInput(simulation.t_stop),
+    step: resolveNumericInput(simulation.step),
+    max_step: resolveNumericInput(simulation.max_step),
+  } satisfies Record<SimulationNumericKey, NumericInputResolution>;
+  const messages: Partial<Record<SimulationNumericKey, string>> = {};
+
+  (Object.keys(resolutions) as SimulationNumericKey[]).forEach((key) => {
+    const resolved = resolutions[key];
+    if (!resolved.ok) {
+      messages[key] = resolved.message;
+    }
+  });
+  if (
+    resolutions.t_start.ok &&
+    resolutions.t_stop.ok &&
+    resolutions.t_stop.value <= resolutions.t_start.value
+  ) {
+    messages.t_stop = "必须大于起始时间";
+  }
+  if (resolutions.step.ok && resolutions.step.value <= 0) {
+    messages.step = "必须大于 0";
+  }
+  if (resolutions.max_step.ok && resolutions.max_step.value <= 0) {
+    messages.max_step = "必须大于 0";
+  }
+  return messages;
+}
+
+type SimulationConfigResolution =
+  | { ok: true; value: ResolvedSimulationConfig }
+  | { ok: false; message: string };
+
+function resolveSimulationConfig(
+  simulation: SimulationConfig,
+): SimulationConfigResolution {
+  const messages = simulationConfigValidationMessages(simulation);
+  const firstInvalidKey = (Object.keys(messages) as SimulationNumericKey[])[0];
+  if (firstInvalidKey) {
+    return {
+      ok: false,
+      message: `仿真设置“${simulationConfigLabels[firstInvalidKey]}”：${messages[firstInvalidKey]}`,
+    };
+  }
+  return {
+    ok: true,
+    value: {
+      t_start: (resolveNumericInput(simulation.t_start) as { ok: true; value: number })
+        .value,
+      t_stop: (resolveNumericInput(simulation.t_stop) as { ok: true; value: number })
+        .value,
+      step: (resolveNumericInput(simulation.step) as { ok: true; value: number })
+        .value,
+      max_step: (
+        resolveNumericInput(simulation.max_step) as { ok: true; value: number }
+      ).value,
+      method: simulation.method,
+    },
+  };
+}
+
 function findDuplicateNames(nodes: SimulationNode[]) {
   const counts = new Map<string, number>();
   nodes.forEach((node) => {
@@ -5236,9 +5477,16 @@ function validateModel(
       return;
     }
     Object.entries(definition.parameters).forEach(([key, parameter]) => {
-      const message = parameterValidationMessage(parameter, node.data.parameters[key] ?? "");
+      const selectedUnit =
+        node.data.parameterUnits[key] ?? parameter.unit ?? "";
+      const message = parameterValidationMessage(
+        parameter,
+        node.data.parameters[key] ?? "",
+        selectedUnit,
+      );
       if (message) {
-        addIssue("error", `${node.data.label}：${parameter.label}${message}`, {
+        const messageSeparator = message.startsWith("等式") ? "：" : "";
+        addIssue("error", `${node.data.label}：${parameter.label}${messageSeparator}${message}`, {
           nodeId: node.id,
         });
       }
@@ -5416,17 +5664,13 @@ function validateModel(
     });
   });
 
-  if (!Number.isFinite(simulation.t_start) || !Number.isFinite(simulation.t_stop)) {
+  const simulationErrors = simulationConfigValidationMessages(simulation);
-    addIssue("error", "仿真起止时间必须是有效数字");
+  (Object.keys(simulationErrors) as SimulationNumericKey[]).forEach((key) => {
-  } else if (simulation.t_stop <= simulation.t_start) {
+    const message = simulationErrors[key];
-    addIssue("error", "仿真结束时间必须大于起始时间");
+    if (message) {
-  }
+      addIssue("error", `仿真设置：${simulationConfigLabels[key]}：${message}`);
-  if (!Number.isFinite(simulation.step) || simulation.step <= 0) {
-    addIssue("error", "采样步长必须大于 0");
-  }
-  if (!Number.isFinite(simulation.max_step) || simulation.max_step <= 0) {
-    addIssue("error", "最大积分步长必须大于 0");
     }
+  });
   if (!SUPPORTED_SOLVER_METHODS.includes(simulation.method)) {
     addIssue("error", "求解器不受支持");
   }
@@ -5548,7 +5792,15 @@ function formatTime(date: Date) {
   return date.toLocaleTimeString("zh-CN", { hour: "2-digit", minute: "2-digit" });
 }
 
-function buildSystemXml(project: ReactFlowProjectPayload) {
+function buildSystemXml(
+  project: ReactFlowProjectPayload,
+  componentDefinitions: ComponentDefinition[],
+) {
+  const simulationResolution = resolveSimulationConfig(project.simulation);
+  if (!simulationResolution.ok) {
+    throw new Error(simulationResolution.message);
+  }
+  const resolvedSimulation = simulationResolution.value;
   const xmlDocument = document.implementation.createDocument("", "System", null);
   const system = xmlDocument.documentElement;
   system.setAttribute("name", project.name);
@@ -5557,16 +5809,22 @@ function buildSystemXml(project: ReactFlowProjectPayload) {
   system.setAttribute("unitSystem", "SI");
 
   const simulation = xmlDocument.createElement("Simulation");
-  simulation.setAttribute("tStart", String(project.simulation.t_start));
+  simulation.setAttribute("tStart", String(resolvedSimulation.t_start));
-  simulation.setAttribute("tStop", String(project.simulation.t_stop));
+  simulation.setAttribute("tStop", String(resolvedSimulation.t_stop));
-  simulation.setAttribute("step", String(project.simulation.step));
+  simulation.setAttribute("step", String(resolvedSimulation.step));
-  simulation.setAttribute("maxStep", String(project.simulation.max_step));
+  simulation.setAttribute("maxStep", String(resolvedSimulation.max_step));
-  simulation.setAttribute("method", project.simulation.method);
+  simulation.setAttribute("method", resolvedSimulation.method);
   const components = xmlDocument.createElement("Components");
   const connections = xmlDocument.createElement("Connections");
   system.append(simulation, components, connections);
 
   project.nodes.forEach((node) => {
+    const definition = componentDefinitions.find(
+      (candidate) => candidate.type === node.data.componentType,
+    );
+    if (!definition) {
+      throw new Error(`组件 ${node.data.label || node.id} 的类型不受支持`);
+    }
     const component = xmlDocument.createElement("Component");
     component.setAttribute("id", node.id);
     component.setAttribute("name", node.data.label);
@@ -5590,9 +5848,20 @@ function buildSystemXml(project: ReactFlowProjectPayload) {
       component.appendChild(port);
     });
     Object.entries(node.data.parameters).forEach(([name, value]) => {
+      const parameterDefinition = definition.parameters[name];
+      const selectedUnit =
+        node.data.parameterUnits?.[name] ?? parameterDefinition?.unit ?? "";
+      const resolved = parameterDefinition
+        ? resolveParameterValue(value, parameterDefinition, selectedUnit)
+        : resolveNumericInput(value);
+      if (!resolved.ok) {
+        throw new Error(
+          `组件“${node.data.label || node.id}”的参数“${parameterDefinition?.label ?? name}”：${resolved.message}`,
+        );
+      }
       const parameter = xmlDocument.createElement("Parameter");
       parameter.setAttribute("name", name);
-      parameter.setAttribute("value", String(value));
+      parameter.setAttribute("value", formatEditableNumber(resolved.value));
       component.appendChild(parameter);
     });
     components.appendChild(component);

frontend/src/ComponentSymbol.tsx

@@ -1,39 +1,43 @@
-import type { ReactNode } from "react";
+import { AmesimPnpl01Symbol } from "./componentSymbols/boundary";
+import {
+  AmesimF000Symbol,
+  AmesimForcSymbol,
+  AmesimLmechn1Symbol,
+  AmesimLstp00aSymbol,
+  AmesimMecmas21Symbol,
+} from "./componentSymbols/mechanical";
+import {
+  AmesimHeliumMediumSymbol,
+  AmesimIdealAirMediumSymbol,
+} from "./componentSymbols/media";
+import {
+  AmesimPn3Node2Symbol,
+  AmesimP4Node2Symbol,
+  AmesimPnl0001Symbol,
+  AmesimPnl0002Symbol,
+  AmesimPnl0003Symbol,
+  AmesimPnl00rSymbol,
+  AmesimPnor001Symbol,
+  AmesimPnvo001FixedSymbol,
+  AmesimPnvo001SignalSymbol,
+} from "./componentSymbols/pneumatic";
+import { SymbolSvg } from "./componentSymbols/primitives";
+import { AmesimStep0Symbol, AmesimUd00Symbol } from "./componentSymbols/signals";
+import { AmesimPnch012Symbol, AmesimPnch023Symbol } from "./componentSymbols/storage";
+import type {
+  ComponentSymbolPresentation,
+  SymbolDefinition,
+} from "./componentSymbols/types";
+
+export type { ComponentSymbolPresentation } from "./componentSymbols/types";
 
 export type ComponentSymbolSurface = "palette" | "canvas";
-export type ComponentSymbolPresentation = "framed" | "bare";
-
 type ComponentSymbolProps = {
   symbol: string;
   surface: ComponentSymbolSurface;
   className?: string;
 };
 
-type SymbolDefinition = {
-  presentation: ComponentSymbolPresentation;
-  render: () => ReactNode;
-};
-
-type SymbolSvgProps = {
-  children: ReactNode;
-  className?: string;
-};
-
-function SymbolSvg({ children, className }: SymbolSvgProps) {
-  return (
-    <svg
-      aria-hidden="true"
-      className={["component-symbol-svg", className].filter(Boolean).join(" ")}
-      fill="none"
-      focusable="false"
-      viewBox="0 0 64 48"
-      xmlns="http://www.w3.org/2000/svg"
-    >
-      {children}
-    </svg>
-  );
-}
-
 function CylinderSymbol() {
   return (
     <SymbolSvg>
@@ -145,28 +149,6 @@ function JunctionSymbol() {
   );
 }
 
-function MediumSymbol({ label }: { label: "Air" | "He" }) {
-  return (
-    <SymbolSvg className="component-symbol-medium-svg">
-      <circle cx="32" cy="24" fill="#ffffff" r="22" stroke="#c026d3" strokeWidth="2" />
-      <text
-        className="component-symbol-medium-label"
-        data-symbol-label={label}
-        dominantBaseline="central"
-        fill="#a21caf"
-        fontFamily="Arial, sans-serif"
-        fontSize={label === "Air" ? 12 : 16}
-        fontWeight="500"
-        textAnchor="middle"
-        x="32"
-        y="24"
-      >
-        {label}
-      </text>
-    </SymbolSvg>
-  );
-}
-
 const symbolRegistry = {
   cylinder: { presentation: "framed", render: CylinderSymbol },
   tank: { presentation: "framed", render: TankSymbol },
@@ -176,13 +158,38 @@ const symbolRegistry = {
   generic: { presentation: "framed", render: GenericSymbol },
   signal: { presentation: "framed", render: SignalSymbol },
   junction: { presentation: "framed", render: JunctionSymbol },
+  amesim_pnpl01: { presentation: "framed", render: AmesimPnpl01Symbol },
+  amesim_pnch023: { presentation: "framed", render: AmesimPnch023Symbol },
+  amesim_pnch012: { presentation: "framed", render: AmesimPnch012Symbol },
+  amesim_pnor001: { presentation: "framed", render: AmesimPnor001Symbol },
+  amesim_pnvo001_fixed: {
+    presentation: "framed",
+    render: AmesimPnvo001FixedSymbol,
+  },
+  amesim_pnvo001: {
+    presentation: "framed",
+    render: AmesimPnvo001SignalSymbol,
+  },
+  amesim_pnl00r: { presentation: "framed", render: AmesimPnl00rSymbol },
+  amesim_pnl0001: { presentation: "framed", render: AmesimPnl0001Symbol },
+  amesim_pnl0002: { presentation: "framed", render: AmesimPnl0002Symbol },
+  amesim_pnl0003: { presentation: "framed", render: AmesimPnl0003Symbol },
+  amesim_pn3node2: { presentation: "framed", render: AmesimPn3Node2Symbol },
+  amesim_p4node2: { presentation: "framed", render: AmesimP4Node2Symbol },
+  amesim_step0: { presentation: "framed", render: AmesimStep0Symbol },
+  amesim_ud00: { presentation: "framed", render: AmesimUd00Symbol },
+  amesim_f000: { presentation: "framed", render: AmesimF000Symbol },
+  amesim_forc: { presentation: "framed", render: AmesimForcSymbol },
+  amesim_mecmas21: { presentation: "framed", render: AmesimMecmas21Symbol },
+  amesim_lstp00a: { presentation: "framed", render: AmesimLstp00aSymbol },
+  amesim_lmechn1: { presentation: "framed", render: AmesimLmechn1Symbol },
   amesim_ideal_air_medium: {
     presentation: "bare",
-    render: () => <MediumSymbol label="Air" />,
+    render: AmesimIdealAirMediumSymbol,
   },
   amesim_helium_medium: {
     presentation: "bare",
-    render: () => <MediumSymbol label="He" />,
+    render: AmesimHeliumMediumSymbol,
   },
 } satisfies Record<string, SymbolDefinition>;
 

frontend/src/ParameterTable.tsx

@@ -32,6 +32,7 @@ export type ParameterTableRow = {
   defaultValue?: string;
   range?: string;
   currentUnit?: string;
+  calculatedValue?: string;
 };
 
 type ParameterTableProps = {
@@ -144,7 +145,8 @@ function rowHasHelpPreview(row: ParameterTableRow) {
       (typeof row.help === "string" && row.help) ||
       row.defaultValue ||
       row.range ||
-      row.currentUnit,
+      row.currentUnit ||
+      row.calculatedValue,
   );
 }
 
@@ -462,10 +464,16 @@ export function ParameterTable({
                   {previewDescription}
                 </span>
               ) : null}
-              {previewRow.defaultValue ||
+              {previewRow.calculatedValue ||
+              previewRow.defaultValue ||
               previewRow.range ||
               previewRow.currentUnit ? (
                 <span className="parameter-help-preview-meta">
+                  {previewRow.calculatedValue ? (
+                    <span data-testid="parameter-calculated-value">
+                      计算值：{previewRow.calculatedValue}
+                    </span>
+                  ) : null}
                   {previewRow.defaultValue ? (
                     <span>默认值：{previewRow.defaultValue}</span>
                   ) : null}

frontend/src/componentSymbols/boundary.tsx

@@ -0,0 +1,15 @@
+import { SYMBOL_ACCENT, SYMBOL_STROKE, SymbolSvg } from "./primitives";
+
+export function AmesimPnpl01Symbol() {
+  return (
+    <SymbolSvg domain="pneumatic">
+      <path d="M2 24h34" stroke={SYMBOL_STROKE} strokeWidth="2" />
+      <path
+        d="m35 17 14 14m0-14L35 31"
+        stroke={SYMBOL_ACCENT}
+        strokeLinecap="round"
+        strokeWidth="3"
+      />
+    </SymbolSvg>
+  );
+}

frontend/src/componentSymbols/mechanical.tsx

@@ -0,0 +1,217 @@
+import {
+  SYMBOL_ACCENT,
+  SYMBOL_FILL,
+  SYMBOL_MUTED,
+  SYMBOL_STROKE,
+  SymbolSvg,
+} from "./primitives";
+
+const MECHANICAL_LINE_WIDTH = 1.8;
+
+const mechanicalStroke = {
+  fill: "none",
+  stroke: SYMBOL_STROKE,
+  strokeLinecap: "round" as const,
+  strokeLinejoin: "round" as const,
+  strokeWidth: MECHANICAL_LINE_WIDTH,
+};
+
+function MechanicalSocket({ side }: { side: "left" | "right" }) {
+  const facingLeft = side === "left";
+  return (
+    <g {...mechanicalStroke}>
+      <path d={facingLeft ? "M2 24h7" : "M55 24h7"} />
+      <path d={facingLeft ? "M15 19H9v10h6" : "M49 19h6v10h-6"} />
+    </g>
+  );
+}
+
+function GuideHatching({ y, upward }: { y: number; upward: boolean }) {
+  const direction = upward ? -1 : 1;
+  return (
+    <g stroke={SYMBOL_MUTED} strokeWidth="1">
+      {[14, 22, 30, 38, 46].map((x) => (
+        <path
+          d={`M${x - 3} ${y + direction * 3}L${x + 3} ${y - direction * 3}`}
+          key={x}
+        />
+      ))}
+    </g>
+  );
+}
+
+export function AmesimF000Symbol() {
+  return (
+    <SymbolSvg className="component-symbol-amesim-f000" domain="mechanical">
+      <path d="M41 24h21" {...mechanicalStroke} />
+      <rect
+        fill={SYMBOL_FILL}
+        height="28"
+        rx="1"
+        stroke={SYMBOL_STROKE}
+        strokeWidth="2.2"
+        width="18"
+        x="23"
+        y="12"
+      />
+      <path d="M27 26h10" stroke={SYMBOL_ACCENT} strokeWidth="2" />
+    </SymbolSvg>
+  );
+}
+
+export function AmesimForcSymbol() {
+  return (
+    <SymbolSvg className="component-symbol-amesim-forc" domain="mechanical">
+      <g
+        fill="none"
+        stroke={SYMBOL_ACCENT}
+        strokeLinecap="round"
+        strokeLinejoin="round"
+        strokeWidth="1.8"
+      >
+        <path d="M2 24h15" />
+        <path d="m11 19 6 5-6 5" />
+      </g>
+      <circle
+        cx="32"
+        cy="24"
+        fill={SYMBOL_FILL}
+        r="12"
+        stroke={SYMBOL_STROKE}
+        strokeWidth="2"
+      />
+      <text
+        dominantBaseline="central"
+        fill={SYMBOL_STROKE}
+        fontFamily="Arial, sans-serif"
+        fontSize="13"
+        fontWeight="600"
+        textAnchor="middle"
+        x="32"
+        y="24"
+      >
+        F
+      </text>
+      <path d="M44 24h6M50 18v12M50 18h8M50 30h8M58 18v12M58 24h4" {...mechanicalStroke} />
+    </SymbolSvg>
+  );
+}
+
+export function AmesimMecmas21Symbol() {
+  return (
+    <SymbolSvg className="component-symbol-amesim-mecmas21" domain="mechanical">
+      <GuideHatching upward y={5} />
+      <GuideHatching upward={false} y={43} />
+      <path d="M10 8h44M10 40h44" stroke={SYMBOL_MUTED} strokeWidth="1.3" />
+      <MechanicalSocket side="left" />
+      <MechanicalSocket side="right" />
+      <rect
+        fill={SYMBOL_FILL}
+        height="26"
+        rx="1"
+        stroke={SYMBOL_STROKE}
+        strokeWidth="2"
+        width="34"
+        x="15"
+        y="11"
+      />
+      <text
+        dominantBaseline="central"
+        fill={SYMBOL_STROKE}
+        fontFamily="Arial, sans-serif"
+        fontSize="12"
+        fontWeight="600"
+        textAnchor="middle"
+        x="31"
+        y="28"
+      >
+        M
+      </text>
+      <path
+        d="M22 18h15m-5-4 5 4-5 4"
+        fill="none"
+        stroke={SYMBOL_ACCENT}
+        strokeLinecap="round"
+        strokeLinejoin="round"
+        strokeWidth="1.8"
+      />
+    </SymbolSvg>
+  );
+}
+
+export function AmesimLstp00aSymbol() {
+  return (
+    <SymbolSvg className="component-symbol-amesim-lstp00a" domain="mechanical">
+      <path d="M2 24h8M54 24h8" {...mechanicalStroke} />
+      <g transform="rotate(90 32 24)">
+        <path d="M32 2v7M32 39v7" {...mechanicalStroke} />
+        <path d="M27 9V5h10v4M27 39v4h10v-4" {...mechanicalStroke} />
+        <rect
+          fill={SYMBOL_FILL}
+          height="3"
+          stroke={SYMBOL_STROKE}
+          strokeWidth="1.6"
+          width="46"
+          x="9"
+          y="10"
+        />
+        <rect
+          fill={SYMBOL_FILL}
+          height="3"
+          stroke={SYMBOL_STROKE}
+          strokeWidth="1.6"
+          width="46"
+          x="9"
+          y="31"
+        />
+        <rect
+          fill={SYMBOL_FILL}
+          height="3"
+          stroke={SYMBOL_STROKE}
+          strokeWidth="1.6"
+          width="46"
+          x="9"
+          y="39"
+        />
+        <path
+          d="M14 13v4c0 2 12 2 12 4s-12 2-12 4 12 2 12 6"
+          fill="none"
+          stroke={SYMBOL_ACCENT}
+          strokeLinecap="round"
+          strokeLinejoin="round"
+          strokeWidth="2"
+        />
+        <path d="M36 18v-5M36 18h14v6H36v7M40 22h6" {...mechanicalStroke} />
+      </g>
+    </SymbolSvg>
+  );
+}
+
+export function AmesimLmechn1Symbol() {
+  const leftPortRows = [7, 12, 17, 22, 27, 32, 37, 42];
+  return (
+    <SymbolSvg className="component-symbol-amesim-lmechn1" domain="mechanical">
+      <rect
+        fill={SYMBOL_FILL}
+        height="44"
+        rx="1"
+        stroke={SYMBOL_STROKE}
+        strokeWidth="1.8"
+        width="12"
+        x="27"
+        y="2"
+      />
+      {leftPortRows.map((y) => (
+        <path
+          d={`M5 ${y}h22`}
+          key={y}
+          stroke={SYMBOL_STROKE}
+          strokeLinecap="round"
+          strokeWidth="1.4"
+        />
+      ))}
+      <path d="M39 24h20" stroke={SYMBOL_STROKE} strokeWidth="1.8" />
+      <circle cx="33" cy="24" fill={SYMBOL_ACCENT} r="2.2" />
+    </SymbolSvg>
+  );
+}

frontend/src/componentSymbols/media.tsx

@@ -0,0 +1,38 @@
+import { SYMBOL_ACCENT, SYMBOL_FILL, SYMBOL_STROKE, SymbolSvg } from "./primitives";
+
+function MediumSymbol({ label }: { label: "Air" | "He" }) {
+  return (
+    <SymbolSvg className="component-symbol-medium-svg" domain="medium">
+      <circle
+        cx="32"
+        cy="24"
+        fill={SYMBOL_FILL}
+        r="21"
+        stroke={SYMBOL_STROKE}
+        strokeWidth="2"
+      />
+      <text
+        className="component-symbol-medium-label"
+        data-symbol-label={label}
+        dominantBaseline="central"
+        fill={SYMBOL_ACCENT}
+        fontFamily="Arial, sans-serif"
+        fontSize={label === "Air" ? 12 : 16}
+        fontWeight="500"
+        textAnchor="middle"
+        x="32"
+        y="24"
+      >
+        {label}
+      </text>
+    </SymbolSvg>
+  );
+}
+
+export function AmesimIdealAirMediumSymbol() {
+  return <MediumSymbol label="Air" />;
+}
+
+export function AmesimHeliumMediumSymbol() {
+  return <MediumSymbol label="He" />;
+}

frontend/src/componentSymbols/pneumatic.tsx

@@ -0,0 +1,233 @@
+import {
+  SYMBOL_ACCENT,
+  SYMBOL_FILL,
+  SYMBOL_MUTED,
+  SYMBOL_STROKE,
+  SymbolSvg,
+} from "./primitives";
+
+const PNEUMATIC_STROKE_WIDTH = 1.7;
+
+function OrificeBody({
+  centerY = 25,
+  leftPortY = centerY,
+}: {
+  centerY?: number;
+  leftPortY?: number;
+}) {
+  const top = centerY - 10;
+  const bottom = centerY + 10;
+  const leftConnector =
+    leftPortY === centerY
+      ? `M2 ${centerY}h18`
+      : `M2 ${leftPortY}h14L20 ${centerY}`;
+
+  return (
+    <>
+      <path
+        d={`${leftConnector}M44 ${centerY}h18M20 ${centerY}h24`}
+        stroke={SYMBOL_STROKE}
+        strokeLinecap="round"
+        strokeWidth={PNEUMATIC_STROKE_WIDTH}
+      />
+      <path
+        d={`M20 ${top}c5 6 9 7 12 7s7-1 12-7M20 ${bottom}c5-6 9-7 12-7s7 1 12 7`}
+        stroke={SYMBOL_STROKE}
+        strokeLinecap="round"
+        strokeWidth={PNEUMATIC_STROKE_WIDTH}
+      />
+    </>
+  );
+}
+
+/** Constant-coefficient pneumatic orifice (AMESim PNOR001). */
+export function AmesimPnor001Symbol() {
+  return (
+    <SymbolSvg className="component-symbol-amesim-pnor001-svg" domain="pneumatic">
+      <OrificeBody centerY={24} />
+    </SymbolSvg>
+  );
+}
+
+/** PNVO001 convenience variant whose opening is fixed by a parameter. */
+export function AmesimPnvo001FixedSymbol() {
+  return (
+    <SymbolSvg
+      className="component-symbol-amesim-pnvo001-fixed-svg"
+      domain="pneumatic"
+    >
+      <OrificeBody centerY={28} />
+      <path
+        d="M43 4 34 20m9-16-2 7-5-3"
+        stroke={SYMBOL_ACCENT}
+        strokeLinecap="round"
+        strokeLinejoin="round"
+        strokeWidth="1.7"
+      />
+    </SymbolSvg>
+  );
+}
+
+/** Signal-modulated pneumatic orifice (AMESim PNVO001 / pn_morifice). */
+export function AmesimPnvo001SignalSymbol() {
+  return (
+    <SymbolSvg
+      className="component-symbol-amesim-pnvo001-signal-svg"
+      domain="pneumatic"
+    >
+      <OrificeBody centerY={25} leftPortY={32} />
+      <path
+        d="M2 16h11l21 5m0 0-7-1m7 1-5 5"
+        stroke={SYMBOL_ACCENT}
+        strokeLinecap="round"
+        strokeLinejoin="round"
+        strokeWidth="1.7"
+      />
+    </SymbolSvg>
+  );
+}
+
+type PipeSection = "C" | "R";
+
+function PipeNetworkBody({ sections }: { sections: readonly PipeSection[] }) {
+  const left = 9;
+  const right = 55;
+  const top = 13;
+  const bottom = 35;
+  const sectionWidth = (right - left) / sections.length;
+
+  return (
+    <>
+      <path
+        d="M2 24h7M55 24h7"
+        stroke={SYMBOL_STROKE}
+        strokeLinecap="round"
+        strokeWidth={PNEUMATIC_STROKE_WIDTH}
+      />
+      <rect
+        fill={SYMBOL_FILL}
+        height={bottom - top}
+        rx="2"
+        stroke={SYMBOL_STROKE}
+        strokeWidth={PNEUMATIC_STROKE_WIDTH}
+        width={right - left}
+        x={left}
+        y={top}
+      />
+      {sections.slice(1).map((_, index) => {
+        const x = left + sectionWidth * (index + 1);
+        return (
+          <path
+            d={`M${x} ${top + 2}v${bottom - top - 4}`}
+            key={x}
+            stroke={SYMBOL_MUTED}
+            strokeWidth="1.1"
+          />
+        );
+      })}
+      {sections.map((section, index) => (
+        <text
+          dominantBaseline="central"
+          fill={section === "R" ? SYMBOL_ACCENT : SYMBOL_MUTED}
+          fontFamily="Arial, sans-serif"
+          fontSize="9"
+          fontWeight="700"
+          key={`${section}-${index}`}
+          textAnchor="middle"
+          x={left + sectionWidth * (index + 0.5)}
+          y="24"
+        >
+          {section}
+        </text>
+      ))}
+    </>
+  );
+}
+
+/** Pure pneumatic resistance line (AMESim PNL00R). */
+export function AmesimPnl00rSymbol() {
+  return (
+    <SymbolSvg className="component-symbol-amesim-pnl00r-svg" domain="pneumatic">
+      <PipeNetworkBody sections={["R"]} />
+    </SymbolSvg>
+  );
+}
+
+/** C-R dynamic pneumatic line (AMESim PNL0001). */
+export function AmesimPnl0001Symbol() {
+  return (
+    <SymbolSvg className="component-symbol-amesim-pnl0001-svg" domain="pneumatic">
+      <PipeNetworkBody sections={["C", "R"]} />
+    </SymbolSvg>
+  );
+}
+
+/** R-C-R dynamic pneumatic line (AMESim PNL0002). */
+export function AmesimPnl0002Symbol() {
+  return (
+    <SymbolSvg className="component-symbol-amesim-pnl0002-svg" domain="pneumatic">
+      <PipeNetworkBody sections={["R", "C", "R"]} />
+    </SymbolSvg>
+  );
+}
+
+/** C-R-C dynamic pneumatic line (AMESim PNL0003). */
+export function AmesimPnl0003Symbol() {
+  return (
+    <SymbolSvg className="component-symbol-amesim-pnl0003-svg" domain="pneumatic">
+      <PipeNetworkBody sections={["C", "R", "C"]} />
+    </SymbolSvg>
+  );
+}
+
+function JunctionTerminal({ x, y }: { x: number; y: number }) {
+  return (
+    <circle
+      cx={x}
+      cy={y}
+      fill={SYMBOL_FILL}
+      r="2"
+      stroke={SYMBOL_STROKE}
+      strokeWidth="1.3"
+    />
+  );
+}
+
+/** Three-port pneumatic junction with one inlet-side and two outlet-side ports. */
+export function AmesimPn3Node2Symbol() {
+  return (
+    <SymbolSvg className="component-symbol-amesim-pn3node2-svg" domain="pneumatic">
+      <path
+        d="M4 24h25M29 24C41 24 42 12 60 12M29 24c12 0 13 12 31 12"
+        stroke={SYMBOL_STROKE}
+        strokeLinecap="round"
+        strokeLinejoin="round"
+        strokeWidth={PNEUMATIC_STROKE_WIDTH}
+      />
+      <circle cx="29" cy="24" fill={SYMBOL_ACCENT} r="3" />
+      <JunctionTerminal x={3} y={24} />
+      <JunctionTerminal x={61} y={12} />
+      <JunctionTerminal x={61} y={36} />
+    </SymbolSvg>
+  );
+}
+
+/** Four-port pneumatic junction with one inlet-side and three outlet-side ports. */
+export function AmesimP4Node2Symbol() {
+  return (
+    <SymbolSvg className="component-symbol-amesim-p4node2-svg" domain="pneumatic">
+      <path
+        d="M4 24h24M28 24C40 24 42 8 60 8M28 24h32M28 24c12 0 14 16 32 16"
+        stroke={SYMBOL_STROKE}
+        strokeLinecap="round"
+        strokeLinejoin="round"
+        strokeWidth={PNEUMATIC_STROKE_WIDTH}
+      />
+      <circle cx="28" cy="24" fill={SYMBOL_ACCENT} r="3" />
+      <JunctionTerminal x={3} y={24} />
+      <JunctionTerminal x={61} y={8} />
+      <JunctionTerminal x={61} y={24} />
+      <JunctionTerminal x={61} y={40} />
+    </SymbolSvg>
+  );
+}

frontend/src/componentSymbols/primitives.tsx

@@ -0,0 +1,41 @@
+import type { ReactNode } from "react";
+
+export type SymbolDomain =
+  | "neutral"
+  | "pneumatic"
+  | "mechanical"
+  | "signal"
+  | "medium";
+
+type SymbolSvgProps = {
+  children: ReactNode;
+  className?: string;
+  domain?: SymbolDomain;
+  viewBox?: string;
+};
+
+export const SYMBOL_STROKE = "var(--component-symbol-stroke, currentColor)";
+export const SYMBOL_FILL = "var(--component-symbol-fill, #ffffff)";
+export const SYMBOL_ACCENT = "var(--component-symbol-accent, currentColor)";
+export const SYMBOL_MUTED = "var(--component-symbol-muted, #64748b)";
+
+export function SymbolSvg({
+  children,
+  className,
+  domain = "neutral",
+  viewBox = "0 0 64 48",
+}: SymbolSvgProps) {
+  return (
+    <svg
+      aria-hidden="true"
+      className={["component-symbol-svg", className].filter(Boolean).join(" ")}
+      data-symbol-domain={domain}
+      fill="none"
+      focusable="false"
+      viewBox={viewBox}
+      xmlns="http://www.w3.org/2000/svg"
+    >
+      {children}
+    </svg>
+  );
+}

frontend/src/componentSymbols/signals.tsx

@@ -0,0 +1,71 @@
+import {
+  SYMBOL_ACCENT,
+  SYMBOL_FILL,
+  SYMBOL_STROKE,
+  SymbolSvg,
+} from "./primitives";
+
+const SIGNAL_LINE_WIDTH = 1.8;
+
+function SignalOutput() {
+  return (
+    <g
+      fill="none"
+      stroke={SYMBOL_STROKE}
+      strokeLinecap="round"
+      strokeLinejoin="round"
+      strokeWidth={SIGNAL_LINE_WIDTH}
+    >
+      <path d="M46 24h14" />
+      <path d="m54 20 6 4-6 4" />
+    </g>
+  );
+}
+
+export function AmesimStep0Symbol() {
+  return (
+    <SymbolSvg className="component-symbol-amesim-step0" domain="signal">
+      <circle
+        cx="27"
+        cy="24"
+        fill={SYMBOL_FILL}
+        r="18"
+        stroke={SYMBOL_STROKE}
+        strokeWidth={SIGNAL_LINE_WIDTH}
+      />
+      <path
+        d="M14 30h8V17h18"
+        fill="none"
+        stroke={SYMBOL_ACCENT}
+        strokeLinecap="square"
+        strokeLinejoin="miter"
+        strokeWidth="2.2"
+      />
+      <SignalOutput />
+    </SymbolSvg>
+  );
+}
+
+export function AmesimUd00Symbol() {
+  return (
+    <SymbolSvg className="component-symbol-amesim-ud00" domain="signal">
+      <circle
+        cx="27"
+        cy="24"
+        fill={SYMBOL_FILL}
+        r="18"
+        stroke={SYMBOL_STROKE}
+        strokeWidth={SIGNAL_LINE_WIDTH}
+      />
+      <path
+        d="M13 30h5l5-10h5l5-9 5 19h3"
+        fill="none"
+        stroke={SYMBOL_ACCENT}
+        strokeLinecap="round"
+        strokeLinejoin="round"
+        strokeWidth="2.2"
+      />
+      <SignalOutput />
+    </SymbolSvg>
+  );
+}

frontend/src/componentSymbols/storage.tsx

@@ -0,0 +1,69 @@
+import {
+  SYMBOL_ACCENT,
+  SYMBOL_FILL,
+  SYMBOL_STROKE,
+  SymbolSvg,
+} from "./primitives";
+
+function ChamberCore({ variable }: { variable: boolean }) {
+  return (
+    <>
+      <circle
+        cx="32"
+        cy="24"
+        fill={SYMBOL_FILL}
+        r="13"
+        stroke={SYMBOL_STROKE}
+        strokeWidth="2"
+      />
+      <text
+        dominantBaseline="central"
+        fill={SYMBOL_ACCENT}
+        fontFamily="Arial, sans-serif"
+        fontSize="13"
+        fontWeight="700"
+        textAnchor="middle"
+        x="32"
+        y="24"
+      >
+        Cp
+      </text>
+      {variable ? (
+        <g
+          fill="none"
+          stroke={SYMBOL_ACCENT}
+          strokeLinecap="round"
+          strokeLinejoin="round"
+          strokeWidth="1.5"
+        >
+          <path d="m20 13-5-5m0 0h4m-4 0v4" />
+          <path d="m44 13 5-5m0 0h-4m4 0v4" />
+          <path d="m20 35-5 5m0 0h4m-4 0v-4" />
+          <path d="m44 35 5 5m0 0h-4m4 0v-4" />
+        </g>
+      ) : null}
+    </>
+  );
+}
+
+export function AmesimPnch023Symbol() {
+  return (
+    <SymbolSvg domain="pneumatic">
+      <path d="M2 24h17M45 24h17" stroke={SYMBOL_STROKE} strokeWidth="2" />
+      <ChamberCore variable={false} />
+    </SymbolSvg>
+  );
+}
+
+export function AmesimPnch012Symbol() {
+  return (
+    <SymbolSvg domain="pneumatic">
+      <path
+        d="M2 16h17M2 32h17M45 16h17M45 32h17"
+        stroke={SYMBOL_STROKE}
+        strokeWidth="2"
+      />
+      <ChamberCore variable />
+    </SymbolSvg>
+  );
+}

frontend/src/componentSymbols/types.ts

@@ -0,0 +1,8 @@
+import type { ReactNode } from "react";
+
+export type ComponentSymbolPresentation = "framed" | "bare";
+
+export type SymbolDefinition = {
+  presentation: ComponentSymbolPresentation;
+  render: () => ReactNode;
+};

frontend/src/parameterExpression.ts

@@ -0,0 +1,458 @@
+export type ParameterExpressionEvaluation =
+  | { ok: true; value: number }
+  | { ok: false; message: string };
+
+const MAX_INPUT_LENGTH = 512;
+const MAX_TOKEN_COUNT = 256;
+const MAX_OPERATION_COUNT = 256;
+const MAX_NESTING_DEPTH = 32;
+const MAX_FUNCTION_ARGUMENTS = 16;
+
+const NUMERIC_LITERAL_PATTERN =
+  /^[+-]?(?:\d+(?:\.\d*)?|\.\d+)(?:[eE][+-]?\d+)?$/;
+const UNSIGNED_NUMBER_PREFIX =
+  /^(?:\d+(?:\.\d*)?|\.\d+)(?:[eE][+-]?\d+)?/;
+
+type TokenKind =
+  | "number"
+  | "identifier"
+  | "operator"
+  | "leftParenthesis"
+  | "rightParenthesis"
+  | "comma"
+  | "end";
+
+type Token = {
+  kind: TokenKind;
+  text: string;
+  position: number;
+  value?: number;
+};
+
+class ParameterExpressionError extends Error {}
+
+/**
+ * Distinguishes a stored equation from an ordinary numeric parameter value.
+ * Invalid non-numeric strings intentionally count as expressions so callers
+ * can run them through the evaluator and present its specific error message.
+ */
+export function isParameterExpressionValue(value: number | string): value is string {
+  if (typeof value !== "string") {
+    return false;
+  }
+  const trimmed = value.trim();
+  if (!trimmed) {
+    return false;
+  }
+  return trimmed.startsWith("=") || !NUMERIC_LITERAL_PATTERN.test(trimmed);
+}
+
+/**
+ * Safely evaluates the arithmetic subset accepted by AMESim-style parameter
+ * fields. This parser never executes JavaScript and cannot access globals,
+ * object properties, or arbitrary functions.
+ */
+export function evaluateParameterExpression(
+  input: string,
+): ParameterExpressionEvaluation {
+  try {
+    let source = input.trim();
+    if (source.startsWith("=")) {
+      source = source.slice(1).trim();
+    }
+    if (!source) {
+      throw new ParameterExpressionError("表达式不能为空");
+    }
+    if (source.length > MAX_INPUT_LENGTH) {
+      throw new ParameterExpressionError(
+        `表达式长度不能超过 ${MAX_INPUT_LENGTH} 个字符`,
+      );
+    }
+
+    const parser = new ParameterExpressionParser(tokenize(source));
+    return { ok: true, value: parser.parse() };
+  } catch (error) {
+    return {
+      ok: false,
+      message:
+        error instanceof ParameterExpressionError
+          ? error.message
+          : "表达式无法计算",
+    };
+  }
+}
+
+function tokenize(source: string): Token[] {
+  const tokens: Token[] = [];
+  let position = 0;
+
+  const pushToken = (token: Token) => {
+    tokens.push(token);
+    if (tokens.length > MAX_TOKEN_COUNT) {
+      throw new ParameterExpressionError(
+        `表达式过于复杂，最多允许 ${MAX_TOKEN_COUNT} 个词元`,
+      );
+    }
+  };
+
+  while (position < source.length) {
+    const character = source[position];
+    if (/\s/.test(character)) {
+      position += 1;
+      continue;
+    }
+
+    if (/\d/.test(character) || (character === "." && /\d/.test(source[position + 1] ?? ""))) {
+      const match = UNSIGNED_NUMBER_PREFIX.exec(source.slice(position));
+      if (!match) {
+        throw new ParameterExpressionError(
+          `第 ${position + 1} 个字符附近的数字格式无效`,
+        );
+      }
+      const text = match[0];
+      const value = Number(text);
+      if (!Number.isFinite(value)) {
+        throw new ParameterExpressionError(`数字“${text}”不是有限数值`);
+      }
+      pushToken({ kind: "number", text, position, value });
+      position += text.length;
+      continue;
+    }
+
+    if (/[A-Za-z_]/.test(character)) {
+      let end = position + 1;
+      while (end < source.length && /[A-Za-z0-9_]/.test(source[end])) {
+        end += 1;
+      }
+      const text = source.slice(position, end);
+      pushToken({ kind: "identifier", text, position });
+      position = end;
+      continue;
+    }
+
+    if (character === "*" && source[position + 1] === "*") {
+      pushToken({ kind: "operator", text: "**", position });
+      position += 2;
+      continue;
+    }
+    if (["+", "-", "*", "/", "^"].includes(character)) {
+      pushToken({ kind: "operator", text: character, position });
+      position += 1;
+      continue;
+    }
+    if (character === "(") {
+      pushToken({ kind: "leftParenthesis", text: character, position });
+      position += 1;
+      continue;
+    }
+    if (character === ")") {
+      pushToken({ kind: "rightParenthesis", text: character, position });
+      position += 1;
+      continue;
+    }
+    if (character === ",") {
+      pushToken({ kind: "comma", text: character, position });
+      position += 1;
+      continue;
+    }
+
+    throw new ParameterExpressionError(
+      `第 ${position + 1} 个字符包含不支持的符号“${character}”`,
+    );
+  }
+
+  tokens.push({ kind: "end", text: "", position: source.length });
+  return tokens;
+}
+
+class ParameterExpressionParser {
+  private index = 0;
+  private operationCount = 0;
+  private readonly tokens: readonly Token[];
+
+  constructor(tokens: readonly Token[]) {
+    this.tokens = tokens;
+  }
+
+  parse() {
+    const value = this.parseAdditive(0);
+    const trailing = this.current();
+    if (trailing.kind !== "end") {
+      throw new ParameterExpressionError(
+        `第 ${trailing.position + 1} 个字符附近存在多余内容“${trailing.text}”`,
+      );
+    }
+    return ensureFinite(value, "表达式的计算结果");
+  }
+
+  private parseAdditive(depth: number): number {
+    let value = this.parseMultiplicative(depth);
+    while (this.isOperator("+") || this.isOperator("-")) {
+      const operator = this.advance().text;
+      const right = this.parseMultiplicative(depth);
+      this.countOperation();
+      value = ensureFinite(
+        operator === "+" ? value + right : value - right,
+        `运算“${operator}”的结果`,
+      );
+    }
+    return value;
+  }
+
+  private parseMultiplicative(depth: number): number {
+    let value = this.parseUnary(depth);
+    while (this.isOperator("*") || this.isOperator("/")) {
+      const operator = this.advance().text;
+      const right = this.parseUnary(depth);
+      this.countOperation();
+      if (operator === "/" && right === 0) {
+        throw new ParameterExpressionError("除数不能为 0");
+      }
+      value = ensureFinite(
+        operator === "*" ? value * right : value / right,
+        `运算“${operator}”的结果`,
+      );
+    }
+    return value;
+  }
+
+  private parseUnary(depth: number): number {
+    this.assertDepth(depth);
+    if (this.isOperator("+") || this.isOperator("-")) {
+      const operator = this.advance().text;
+      this.countOperation();
+      const operand = this.parseUnary(depth + 1);
+      return ensureFinite(
+        operator === "+" ? operand : -operand,
+        `一元运算“${operator}”的结果`,
+      );
+    }
+    return this.parsePower(depth);
+  }
+
+  private parsePower(depth: number): number {
+    this.assertDepth(depth);
+    const base = this.parsePrimary(depth);
+    if (!this.isOperator("^") && !this.isOperator("**")) {
+      return base;
+    }
+    const operator = this.advance().text;
+    const exponent = this.parseUnary(depth + 1);
+    this.countOperation();
+    return ensureFinite(Math.pow(base, exponent), `运算“${operator}”的结果`);
+  }
+
+  private parsePrimary(depth: number): number {
+    this.assertDepth(depth);
+    const token = this.current();
+    if (token.kind === "number") {
+      this.advance();
+      return ensureFinite(token.value ?? Number.NaN, `数字“${token.text}”`);
+    }
+
+    if (token.kind === "identifier") {
+      this.advance();
+      const name = token.text.toLowerCase();
+      if (this.current().kind === "leftParenthesis") {
+        return this.parseFunctionCall(name, token.text, depth + 1);
+      }
+      if (name === "pi") {
+        return Math.PI;
+      }
+      if (name === "e") {
+        return Math.E;
+      }
+      throw new ParameterExpressionError(`未知标识符“${token.text}”`);
+    }
+
+    if (token.kind === "leftParenthesis") {
+      this.advance();
+      const value = this.parseAdditive(depth + 1);
+      this.expect("rightParenthesis", "缺少右括号“)”");
+      return value;
+    }
+
+    if (token.kind === "end") {
+      throw new ParameterExpressionError("表达式结尾缺少数字、常量或函数");
+    }
+    throw new ParameterExpressionError(
+      `第 ${token.position + 1} 个字符附近需要数字、常量或函数`,
+    );
+  }
+
+  private parseFunctionCall(
+    normalizedName: string,
+    sourceName: string,
+    depth: number,
+  ): number {
+    this.assertDepth(depth);
+    this.expect("leftParenthesis", `函数 ${sourceName} 后缺少左括号“(”`);
+    const arguments_: number[] = [];
+    if (this.current().kind !== "rightParenthesis") {
+      while (true) {
+        if (arguments_.length >= MAX_FUNCTION_ARGUMENTS) {
+          throw new ParameterExpressionError(
+            `函数 ${sourceName} 最多接受 ${MAX_FUNCTION_ARGUMENTS} 个参数`,
+          );
+        }
+        arguments_.push(this.parseAdditive(depth));
+        if (this.current().kind !== "comma") {
+          break;
+        }
+        this.advance();
+        if (this.current().kind === "rightParenthesis") {
+          throw new ParameterExpressionError(`函数 ${sourceName} 的逗号后缺少参数`);
+        }
+      }
+    }
+    this.expect("rightParenthesis", `函数 ${sourceName} 缺少右括号“)”`);
+    this.countOperation();
+    return evaluateFunction(normalizedName, sourceName, arguments_);
+  }
+
+  private current() {
+    return this.tokens[this.index] ?? this.tokens[this.tokens.length - 1];
+  }
+
+  private advance() {
+    const token = this.current();
+    if (token.kind !== "end") {
+      this.index += 1;
+    }
+    return token;
+  }
+
+  private expect(kind: TokenKind, message: string) {
+    if (this.current().kind !== kind) {
+      throw new ParameterExpressionError(message);
+    }
+    return this.advance();
+  }
+
+  private isOperator(operator: string) {
+    const token = this.current();
+    return token.kind === "operator" && token.text === operator;
+  }
+
+  private assertDepth(depth: number) {
+    if (depth > MAX_NESTING_DEPTH) {
+      throw new ParameterExpressionError(
+        `表达式嵌套层级不能超过 ${MAX_NESTING_DEPTH} 层`,
+      );
+    }
+  }
+
+  private countOperation() {
+    this.operationCount += 1;
+    if (this.operationCount > MAX_OPERATION_COUNT) {
+      throw new ParameterExpressionError(
+        `表达式过于复杂，最多允许 ${MAX_OPERATION_COUNT} 次运算`,
+      );
+    }
+  }
+}
+
+function evaluateFunction(
+  normalizedName: string,
+  sourceName: string,
+  arguments_: readonly number[],
+) {
+  const requireCount = (expected: number) => {
+    if (arguments_.length !== expected) {
+      throw new ParameterExpressionError(
+        `函数 ${sourceName} 需要 ${expected} 个参数，当前提供了 ${arguments_.length} 个`,
+      );
+    }
+  };
+  const requireAtLeastOne = () => {
+    if (arguments_.length === 0) {
+      throw new ParameterExpressionError(`函数 ${sourceName} 至少需要 1 个参数`);
+    }
+  };
+
+  let value: number;
+  switch (normalizedName) {
+    case "sqrt":
+      requireCount(1);
+      if (arguments_[0] < 0) {
+        throw new ParameterExpressionError("函数 sqrt 的参数不能小于 0");
+      }
+      value = Math.sqrt(arguments_[0]);
+      break;
+    case "abs":
+      requireCount(1);
+      value = Math.abs(arguments_[0]);
+      break;
+    case "sin":
+      requireCount(1);
+      value = Math.sin(arguments_[0]);
+      break;
+    case "cos":
+      requireCount(1);
+      value = Math.cos(arguments_[0]);
+      break;
+    case "tan":
+      requireCount(1);
+      value = Math.tan(arguments_[0]);
+      break;
+    case "asin":
+      requireCount(1);
+      if (arguments_[0] < -1 || arguments_[0] > 1) {
+        throw new ParameterExpressionError("函数 asin 的参数必须位于 [-1, 1]");
+      }
+      value = Math.asin(arguments_[0]);
+      break;
+    case "acos":
+      requireCount(1);
+      if (arguments_[0] < -1 || arguments_[0] > 1) {
+        throw new ParameterExpressionError("函数 acos 的参数必须位于 [-1, 1]");
+      }
+      value = Math.acos(arguments_[0]);
+      break;
+    case "atan":
+      requireCount(1);
+      value = Math.atan(arguments_[0]);
+      break;
+    case "exp":
+      requireCount(1);
+      value = Math.exp(arguments_[0]);
+      break;
+    case "ln":
+    case "log":
+      requireCount(1);
+      if (arguments_[0] <= 0) {
+        throw new ParameterExpressionError(`函数 ${sourceName} 的参数必须大于 0`);
+      }
+      value = Math.log(arguments_[0]);
+      break;
+    case "log10":
+      requireCount(1);
+      if (arguments_[0] <= 0) {
+        throw new ParameterExpressionError("函数 log10 的参数必须大于 0");
+      }
+      value = Math.log10(arguments_[0]);
+      break;
+    case "min":
+      requireAtLeastOne();
+      value = Math.min(...arguments_);
+      break;
+    case "max":
+      requireAtLeastOne();
+      value = Math.max(...arguments_);
+      break;
+    case "pow":
+      requireCount(2);
+      value = Math.pow(arguments_[0], arguments_[1]);
+      break;
+    default:
+      throw new ParameterExpressionError(`不支持函数“${sourceName}”`);
+  }
+  return ensureFinite(value, `函数 ${sourceName} 的计算结果`);
+}
+
+function ensureFinite(value: number, context: string) {
+  if (!Number.isFinite(value)) {
+    throw new ParameterExpressionError(`${context}不是有限数值`);
+  }
+  return value;
+}

frontend/src/styles.css

@@ -964,6 +964,42 @@ textarea {
   width: 100%;
   height: 100%;
   overflow: visible;
+  shape-rendering: geometricPrecision;
+}
+
+.component-symbol-svg[data-symbol-domain="neutral"] {
+  --component-symbol-stroke: #334155;
+  --component-symbol-fill: #f8fafc;
+  --component-symbol-accent: #2563eb;
+  --component-symbol-muted: #94a3b8;
+}
+
+.component-symbol-svg[data-symbol-domain="pneumatic"] {
+  --component-symbol-stroke: #a12b70;
+  --component-symbol-fill: #fff8fc;
+  --component-symbol-accent: #bd2779;
+  --component-symbol-muted: #d69aba;
+}
+
+.component-symbol-svg[data-symbol-domain="mechanical"] {
+  --component-symbol-stroke: #1f9d42;
+  --component-symbol-fill: #f4fff6;
+  --component-symbol-accent: #15803d;
+  --component-symbol-muted: #86c994;
+}
+
+.component-symbol-svg[data-symbol-domain="signal"] {
+  --component-symbol-stroke: #ef4444;
+  --component-symbol-fill: #fff8f8;
+  --component-symbol-accent: #dc2626;
+  --component-symbol-muted: #f5a3a3;
+}
+
+.component-symbol-svg[data-symbol-domain="medium"] {
+  --component-symbol-stroke: #c026d3;
+  --component-symbol-fill: #ffffff;
+  --component-symbol-accent: #a21caf;
+  --component-symbol-muted: #e879f9;
 }
 
 .component-symbol-medium-label {

frontend/tests/e2e/component-symbols.spec.ts

@@ -0,0 +1,156 @@
+import { expect, test } from "@playwright/test";
+
+type SymbolCase = {
+  category: string;
+  domain: "medium" | "pneumatic" | "signal" | "mechanical";
+  modelType: string;
+};
+
+const symbolCases: SymbolCase[] = [
+  { category: "media", domain: "medium", modelType: "amesim_ideal_air_medium" },
+  { category: "media", domain: "medium", modelType: "amesim_helium_medium" },
+  { category: "storage", domain: "pneumatic", modelType: "amesim_pnch023" },
+  { category: "storage", domain: "pneumatic", modelType: "amesim_pnch012" },
+  { category: "flow", domain: "pneumatic", modelType: "amesim_pnor001" },
+  { category: "flow", domain: "pneumatic", modelType: "amesim_pnvo001_fixed" },
+  { category: "flow", domain: "pneumatic", modelType: "amesim_pnvo001" },
+  { category: "flow", domain: "pneumatic", modelType: "amesim_pnl00r" },
+  { category: "flow", domain: "pneumatic", modelType: "amesim_pnl0001" },
+  { category: "flow", domain: "pneumatic", modelType: "amesim_pnl0002" },
+  { category: "flow", domain: "pneumatic", modelType: "amesim_pnl0003" },
+  { category: "junctions", domain: "pneumatic", modelType: "amesim_pn3node2" },
+  { category: "junctions", domain: "pneumatic", modelType: "amesim_p4node2" },
+  { category: "boundary", domain: "pneumatic", modelType: "amesim_pnpl01" },
+  { category: "signals", domain: "signal", modelType: "amesim_step0" },
+  { category: "signals", domain: "signal", modelType: "amesim_ud00" },
+  { category: "mechanical", domain: "mechanical", modelType: "amesim_f000" },
+  { category: "mechanical", domain: "mechanical", modelType: "amesim_forc" },
+  { category: "mechanical", domain: "mechanical", modelType: "amesim_mecmas21" },
+  { category: "mechanical", domain: "mechanical", modelType: "amesim_lstp00a" },
+  { category: "mechanical", domain: "mechanical", modelType: "amesim_lmechn1" },
+];
+
+const categoryLabels: Record<string, string> = {
+  boundary: "边界元件",
+  flow: "流动元件",
+  junctions: "连接元件",
+  mechanical: "机械元件",
+  media: "介质物性",
+  signals: "信号元件",
+  storage: "储能元件",
+};
+
+test.beforeEach(async ({ page }) => {
+  await page.addInitScript(() => {
+    const preparedKey = "system-simulation-flow:component-symbols-prepared";
+    if (window.sessionStorage.getItem(preparedKey) !== "1") {
+      window.localStorage.clear();
+      window.sessionStorage.clear();
+      window.sessionStorage.setItem(preparedKey, "1");
+    }
+    window.location.hash = "#/modeling";
+  });
+  await page.route("**/api/components/catalog", async (route) => {
+    await route.fulfill({
+      status: 200,
+      contentType: "application/json",
+      body: JSON.stringify({
+        schemaVersion: 1,
+        libraries: [
+          {
+            id: "amesim",
+            label: "AMESim 组件库",
+            version: "0.2.0",
+            sourcePackage: "tests.e2e.amesim-symbols",
+            temporary: true,
+            order: 1,
+            components: symbolCases.map((item, index) => ({
+              type: item.modelType,
+              label: item.modelType,
+              modelType: item.modelType,
+              modelVersion: "0.1.0",
+              symbol: item.modelType,
+              order: index + 1,
+              category: {
+                id: item.category,
+                label: categoryLabels[item.category],
+                order: Object.keys(categoryLabels).indexOf(item.category) + 1,
+              },
+              ports: [],
+              parameters: [],
+            })),
+          },
+        ],
+      }),
+    });
+  });
+});
+
+test("全部已移植 AMESim 模型使用专属图标及正确领域配色", async ({ page }) => {
+  await page.goto("/");
+
+  const palette = page.locator("aside.palette");
+  await expect(palette.locator('[data-component-symbol^="amesim_"]')).toHaveCount(
+    symbolCases.length,
+  );
+  await expect(palette.locator('[data-component-symbol="generic"]')).toHaveCount(0);
+
+  for (const item of symbolCases) {
+    const symbol = palette.locator(`[data-component-symbol="${item.modelType}"]`);
+    await expect(symbol).toHaveCount(1);
+    await expect(symbol.locator("svg")).toHaveAttribute("data-symbol-domain", item.domain);
+    await expect(symbol).toHaveAttribute(
+      "data-symbol-presentation",
+      item.domain === "medium" ? "bare" : "framed",
+    );
+  }
+});
+
+test("旧工程保存的通用图标会按当前目录定义升级", async ({ page }) => {
+  await page.goto("/");
+  await page.evaluate(() => {
+    window.localStorage.setItem(
+      "system-simulation-flow:autosave",
+      JSON.stringify({
+        name: "legacy-symbol-project",
+        nodes: [
+          {
+            id: "amesim_pnl0001_1",
+            type: "simulationComponent",
+            position: { x: 200, y: 160 },
+            data: {
+              label: "amesim_pnl0001_1",
+              componentType: "amesim_pnl0001",
+              modelType: "amesim_pnl0001",
+              symbol: "pipe",
+              ports: [],
+              parameters: {},
+              parameterUnits: {},
+              rotation: 0,
+              mirrored: false,
+            },
+          },
+        ],
+        edges: [],
+        simulation: {
+          t_start: 0,
+          t_stop: 1,
+          step: 0.1,
+          max_step: 0.05,
+          method: "BDF",
+        },
+      }),
+    );
+  });
+  await page.reload();
+
+  await page.getByRole("button", { name: "恢复", exact: true }).click();
+  const restoredNode = page.locator(
+    '.flow-canvas .react-flow__node[data-id="amesim_pnl0001_1"]',
+  );
+  await expect(restoredNode).toBeVisible();
+  await expect(
+    restoredNode.locator('[data-component-symbol="amesim_pnl0001"]'),
+  ).toBeVisible();
+  await expect(restoredNode.locator('[data-component-symbol="pipe"]')).toHaveCount(0);
+});

frontend/tests/e2e/parameter-expression.spec.ts

@@ -0,0 +1,42 @@
+import { expect, test } from "@playwright/test";
+
+import { evaluateParameterExpression } from "../../src/parameterExpression";
+
+function expectExpressionValue(expression: string, expected: number) {
+  const result = evaluateParameterExpression(expression);
+  expect(result.ok, result.ok ? undefined : result.message).toBe(true);
+  if (result.ok) {
+    expect(result.value).toBeCloseTo(expected, 10);
+  }
+}
+
+test("安全解析 AMESim 风格的算术、幂与科学计数等式", () => {
+  expectExpressionValue("=3.14*10^2/4", 78.5);
+  expectExpressionValue("(2+3)*4", 20);
+  expectExpressionValue("2^3^2", 512);
+  expectExpressionValue("-2^2", -4);
+  expectExpressionValue("2.5E-3", 0.0025);
+});
+
+test("支持有限的数学常量与白名单函数", () => {
+  expectExpressionValue("sqrt(16)+abs(-2)", 6);
+  expectExpressionValue("sin(pi/2)+ln(e)", 2);
+  expectExpressionValue("max(1, 5, 3)+pow(2, 3)", 13);
+});
+
+test("拒绝除零、非法定义域、未知变量和任意代码", () => {
+  for (const expression of [
+    "1/0",
+    "sqrt(-1)",
+    "unknown+1",
+    "window.alert(1)",
+    "1+*2",
+    "1e309",
+  ]) {
+    const result = evaluateParameterExpression(expression);
+    expect(result.ok, expression).toBe(false);
+    if (!result.ok) {
+      expect(result.message.length).toBeGreaterThan(0);
+    }
+  }
+});

frontend/tests/e2e/parameter-table.spec.ts

@@ -201,3 +201,108 @@ test("参数表列宽可调整并在刷新后保留", async ({ page }) => {
   await page.keyboard.press("ArrowRight");
   await expect(reloadedSeparator).toHaveAttribute("aria-valuenow", "120");
 });
+
+test("组件参数公式保留原式，并在说明中显示计算值且 XML 只写数值", async ({
+  page,
+}) => {
+  await page.goto("/");
+  await addPneumaticTestComponent(page);
+
+  const expression = "3.14*10^2/4";
+  const componentTable = page.getByRole("table", { name: "组件参数" });
+  const pressureRow = parameterRow(componentTable, "参考压力");
+  const pressureInput = page.getByLabel("参考压力", { exact: true });
+
+  await page.getByLabel("参考压力单位").selectOption("kPa");
+  await pressureInput.fill(expression);
+  await pressureInput.press("Enter");
+
+  await expect(pressureInput).toHaveValue(expression);
+  await expect(pressureRow).not.toContainText("78.5");
+
+  await pressureRow.hover();
+  await page.waitForTimeout(600);
+  const preview = page.locator("body > #parameter-help-preview");
+  await expect(preview).toBeVisible();
+  await expect(preview.getByTestId("parameter-calculated-value")).toContainText(
+    "78.5",
+  );
+  await expect(preview.getByTestId("parameter-calculated-value")).toContainText(
+    "kPa",
+  );
+
+  await page.getByRole("button", { name: "生成系统 XML", exact: true }).click();
+  const consolePanel = page.getByRole("complementary", {
+    name: "仿真控制台",
+    exact: true,
+  });
+  const xmlBlock = consolePanel.getByLabel("生成的系统 XML");
+  await expect(xmlBlock).toContainText(
+    '<Parameter name="reference_pressure" value="78500"',
+  );
+  await expect(xmlBlock).not.toContainText(expression);
+
+  await page.getByRole("button", { name: "保存工程", exact: true }).click();
+  await pressureInput.fill("120");
+  await pressureInput.press("Enter");
+  await page.getByRole("button", { name: "加载工程", exact: true }).click();
+  await page
+    .locator('.flow-canvas .react-flow__node[data-id="amesim_pneumatic_test_1"]')
+    .click();
+  await expect(page.getByLabel("参考压力", { exact: true })).toHaveValue(
+    expression,
+  );
+});
+
+test("非法组件参数公式显示错误并阻止 XML 生成", async ({ page }) => {
+  await page.goto("/");
+  await addPneumaticTestComponent(page);
+
+  const invalidExpression = "3.14*/4";
+  const componentTable = page.getByRole("table", { name: "组件参数" });
+  const pressureInput = page.getByLabel("参考压力", { exact: true });
+
+  await pressureInput.fill(invalidExpression);
+  await pressureInput.press("Enter");
+
+  await expect(pressureInput).toHaveValue(invalidExpression);
+  await expect(pressureInput).toHaveAttribute("aria-invalid", "true");
+  await expect(
+    componentTable.locator(".parameter-table-message-row .field-error"),
+  ).toBeVisible();
+
+  await page.getByRole("button", { name: "生成系统 XML", exact: true }).click();
+  const consolePanel = page.getByRole("complementary", {
+    name: "仿真控制台",
+    exact: true,
+  });
+  await expect(consolePanel).toContainText("XML 生成失败");
+  await expect(consolePanel).toContainText("参考压力");
+  await expect(consolePanel.getByLabel("生成的系统 XML")).toHaveCount(0);
+});
+
+test("仿真数值设置同样保留公式，并在执行协议中使用计算值", async ({
+  page,
+}) => {
+  await page.goto("/");
+
+  const expression = "1+2*3";
+  const simulationTable = page.getByRole("table", { name: "仿真设置" });
+  const stopRow = parameterRow(simulationTable, "结束时间");
+  const stopInput = page.getByLabel("结束时间", { exact: true });
+  await stopInput.fill(expression);
+  await stopInput.press("Enter");
+
+  await expect(stopInput).toHaveValue(expression);
+  await expect(stopRow).not.toContainText("7");
+  await stopRow.hover();
+  await page.waitForTimeout(600);
+  await expect(
+    page.getByTestId("parameter-calculated-value"),
+  ).toContainText("7 s");
+
+  await page.getByRole("button", { name: "生成系统 XML", exact: true }).click();
+  const xmlBlock = page.getByLabel("生成的系统 XML");
+  await expect(xmlBlock).toContainText('tStop="7"');
+  await expect(xmlBlock).not.toContainText(expression);
+});

tests/test_amesim_helium_step_long_run.py

@@ -0,0 +1,256 @@
+from __future__ import annotations
+
+import math
+import unittest
+
+from app.main import (
+    ReactFlowProjectPayload,
+    build_reactflow_system_xml,
+    compile_reactflow_network,
+    run_system_xml_simulation,
+)
+from app.system_xml import validate_system_xml_document
+from tests.test_generic_system_xml_simulation import component_node, physical_edge
+from tests.test_system_xml_protocol import physical_port
+
+
+def _signal_port(name: str, role: str, side: str) -> dict[str, str | None]:
+    return {
+        "name": name,
+        "kind": "signal",
+        "domain": "signal",
+        "nominalRole": role,
+        "positiveFlowDirection": None,
+        "side": side,
+    }
+
+
+def _signal_edge(
+    edge_id: str,
+    source: str,
+    source_port: str,
+    target: str,
+    target_port: str,
+) -> dict[str, str]:
+    return {
+        "id": edge_id,
+        "source": source,
+        "sourceHandle": source_port,
+        "target": target,
+        "targetHandle": target_port,
+    }
+
+
+def _plug(component_id: str) -> dict[str, object]:
+    return component_node(
+        component_id,
+        "amesim_pnpl01",
+        [physical_port("port_1", "bidirectional", "left")],
+        {},
+    )
+
+
+def helium_step_equalization_project() -> ReactFlowProjectPayload:
+    """Programmatic form of the user XML that failed at the 3.04 s sample."""
+
+    return ReactFlowProjectPayload(
+        name="amesim-helium-step-equalization-regression",
+        nodes=[
+            component_node(
+                "amesim_helium_medium_1",
+                "amesim_helium_medium",
+                [],
+                {"gi": 1.0, "property_model": 0.0},
+            ),
+            component_node(
+                "amesim_pnch023_1",
+                "amesim_pnch023",
+                [
+                    physical_port("port_1", "bidirectional", "left"),
+                    physical_port("port_2", "bidirectional", "right"),
+                ],
+                {
+                    "gi": 1.0,
+                    "cvol": 0.057,
+                    "kth": 0.0,
+                    "sth": 0.1,
+                    "extemp": 293.15,
+                    "p0": 15_300_000.0,
+                    "T0": 293.15,
+                },
+            ),
+            component_node(
+                "amesim_pnch012_1",
+                "amesim_pnch012",
+                [
+                    physical_port("port_1", "bidirectional", "left"),
+                    physical_port("port_2", "bidirectional", "right"),
+                    physical_port("port_3", "bidirectional", "left"),
+                    physical_port("port_4", "bidirectional", "right"),
+                ],
+                {
+                    "gi": 1.0,
+                    "cvol0": 0.015,
+                    "kth": 1500.0,
+                    "sth": 0.7,
+                    "extemp": 293.15,
+                    "p0": 100_000.0,
+                    "T0": 293.15,
+                    "vol1": 0.0,
+                    "vol2": 0.0,
+                    "vol3": 0.0,
+                    "vol4": 0.0,
+                    "dvol1": 0.0,
+                    "dvol2": 0.0,
+                    "dvol3": 0.0,
+                    "dvol4": 0.0,
+                },
+            ),
+            component_node(
+                "amesim_pnvo001_1",
+                "amesim_pnvo001",
+                [
+                    _signal_port("res", "input", "left"),
+                    physical_port("port_2", "bidirectional", "left"),
+                    physical_port("port_3", "bidirectional", "right"),
+                ],
+                {
+                    "gi": 1.0,
+                    "cq": 0.45,
+                    "area0": 7.85e-5,
+                    "Cv": 0.5,
+                    "Kv": 0.4,
+                    "flowset": 1.0,
+                    "opening0": 1.0,
+                },
+            ),
+            component_node(
+                "amesim_step0_1",
+                "amesim_step0",
+                [_signal_port("out", "output", "right")],
+                {"initial": 0.0, "final": 1.0, "time": 0.04},
+            ),
+            _plug("amesim_pnpl01_1"),
+            _plug("amesim_pnpl01_2"),
+            _plug("amesim_pnpl01_3"),
+            _plug("amesim_pnpl01_4"),
+        ],
+        edges=[
+            physical_edge(
+                "edge-high-plug",
+                "amesim_pnpl01_1",
+                "port_1",
+                "amesim_pnch023_1",
+                "port_1",
+            ),
+            physical_edge(
+                "edge-high-valve",
+                "amesim_pnch023_1",
+                "port_2",
+                "amesim_pnvo001_1",
+                "port_2",
+            ),
+            physical_edge(
+                "edge-valve-low",
+                "amesim_pnvo001_1",
+                "port_3",
+                "amesim_pnch012_1",
+                "port_3",
+            ),
+            physical_edge(
+                "edge-low-port-4",
+                "amesim_pnch012_1",
+                "port_4",
+                "amesim_pnpl01_4",
+                "port_1",
+            ),
+            physical_edge(
+                "edge-low-port-2",
+                "amesim_pnch012_1",
+                "port_2",
+                "amesim_pnpl01_3",
+                "port_1",
+            ),
+            physical_edge(
+                "edge-low-port-1",
+                "amesim_pnpl01_2",
+                "port_1",
+                "amesim_pnch012_1",
+                "port_1",
+            ),
+            _signal_edge(
+                "edge-step-valve",
+                "amesim_step0_1",
+                "out",
+                "amesim_pnvo001_1",
+                "res",
+            ),
+        ],
+        simulation={
+            "t_start": 0.0,
+            "t_stop": 10.0,
+            "step": 0.02,
+            "max_step": 0.002,
+            "method": "BDF",
+        },
+    )
+
+
+class AmesimHeliumStepLongRunTests(unittest.TestCase):
+    def test_helium_step_equalization_completes_beyond_3_04_seconds(self) -> None:
+        project = helium_step_equalization_project()
+        network = compile_reactflow_network(project)
+        self.assertEqual(
+            network.components["amesim_pnch023_1"].medium.name,
+            "AMESimHeliumPengRobinson",
+        )
+        self.assertEqual(
+            network.components["amesim_pnch012_1"].medium.name,
+            "AMESimHeliumPengRobinson",
+        )
+
+        xml = build_reactflow_system_xml(project)
+        report = validate_system_xml_document(xml)
+        self.assertTrue(report.valid, report.as_dict())
+
+        result = run_system_xml_simulation(xml)
+
+        self.assertTrue(result["success"], result["message"])
+        self.assertEqual(result["status"], "completed")
+        self.assertAlmostEqual(result["simulatedUntil"], 10.0)
+        self.assertEqual(result["diagnostics"]["signal"]["eventTimes"], [0.04])
+        self.assertLessEqual(
+            result["diagnostics"]["pressureFlow"]["maxEvaluationsPerSolve"],
+            5,
+        )
+        self.assertLessEqual(
+            result["diagnostics"]["pressureFlow"]["maxScaledResidual"],
+            1.0e-7,
+        )
+
+        series = result["series"]
+        self.assertIn(3.04, series["time"])
+        self.assertTrue(
+            all(
+                math.isfinite(value)
+                for values in series.values()
+                for value in values
+            )
+        )
+
+        high_pressure = series["amesim_pnch023_1.p"]
+        low_pressure = series["amesim_pnch012_1.p"]
+        initial_pressure_gap = abs(high_pressure[0] - low_pressure[0])
+        final_pressure_gap = abs(high_pressure[-1] - low_pressure[-1])
+        self.assertLess(high_pressure[-1], high_pressure[0])
+        self.assertGreater(low_pressure[-1], low_pressure[0])
+        self.assertLess(final_pressure_gap, initial_pressure_gap)
+        self.assertLess(final_pressure_gap, 10.0)
+        self.assertLess(
+            abs(series["amesim_pnvo001_1.port_2.m_flow"][-1]),
+            1.0e-4,
+        )
+
+
+if __name__ == "__main__":
+    unittest.main()

tests/test_amesim_pnvo001_signal_xml.py

@@ -84,6 +84,126 @@ def amesim_pnvo001_signal_project() -> ReactFlowProjectPayload:
     )
 
 
+def high_pressure_helium_step_project() -> ReactFlowProjectPayload:
+    chamber_ports = [
+        physical_port("port_1", "bidirectional", "left"),
+        physical_port("port_2", "bidirectional", "right"),
+    ]
+    return ReactFlowProjectPayload(
+        name="amesim-pnvo001-helium-step-regression",
+        nodes=[
+            component_node(
+                "helium_1",
+                "amesim_helium_medium",
+                [],
+                {"gi": 1.0, "property_model": 0.0},
+            ),
+            component_node(
+                "step_1",
+                "amesim_step0",
+                [signal_port("out", "output", "right")],
+                {"initial": 0.0, "final": 1.0, "time": 0.04},
+            ),
+            component_node(
+                "high_chamber",
+                "amesim_pnch023",
+                chamber_ports,
+                {
+                    "gi": 1.0,
+                    "cvol": 0.057,
+                    "kth": 0.0,
+                    "sth": 0.1,
+                    "extemp": 293.15,
+                    "p0": 15_300_000.0,
+                    "T0": 293.15,
+                },
+            ),
+            component_node(
+                "low_chamber",
+                "amesim_pnch023",
+                chamber_ports,
+                {
+                    "gi": 1.0,
+                    "cvol": 0.015,
+                    "kth": 1500.0,
+                    "sth": 0.7,
+                    "extemp": 293.15,
+                    "p0": 100_000.0,
+                    "T0": 293.15,
+                },
+            ),
+            component_node(
+                "valve_1",
+                "amesim_pnvo001",
+                [
+                    signal_port("res", "input", "left"),
+                    physical_port("port_2", "bidirectional", "left"),
+                    physical_port("port_3", "bidirectional", "right"),
+                ],
+                {
+                    "gi": 1.0,
+                    "cq": 0.45,
+                    "area0": 7.85e-5,
+                    "Cv": 0.5,
+                    "Kv": 0.4,
+                    "flowset": 1.0,
+                    "opening0": 1.0,
+                },
+            ),
+            component_node(
+                "high_plug",
+                "amesim_pnpl01",
+                [physical_port("port_1", "bidirectional", "left")],
+                {},
+            ),
+            component_node(
+                "low_plug",
+                "amesim_pnpl01",
+                [physical_port("port_1", "bidirectional", "left")],
+                {},
+            ),
+        ],
+        edges=[
+            signal_edge("signal-1", "step_1", "out", "valve_1", "res"),
+            physical_edge(
+                "edge-high-plug",
+                "high_plug",
+                "port_1",
+                "high_chamber",
+                "port_1",
+            ),
+            physical_edge(
+                "edge-high-valve",
+                "high_chamber",
+                "port_2",
+                "valve_1",
+                "port_2",
+            ),
+            physical_edge(
+                "edge-valve-low",
+                "valve_1",
+                "port_3",
+                "low_chamber",
+                "port_1",
+            ),
+            physical_edge(
+                "edge-low-plug",
+                "low_chamber",
+                "port_2",
+                "low_plug",
+                "port_1",
+            ),
+        ],
+        simulation={
+            "t_start": 0.0,
+            "t_stop": 0.042,
+            "step": 0.002,
+            "max_step": 0.002,
+            "method": "BDF",
+        },
+    )
+
+
 class AmesimPnvo001SignalXmlTests(unittest.TestCase):
     def test_signal_project_compiles_with_signal_connection(self) -> None:
         network = compile_reactflow_network(amesim_pnvo001_signal_project())
@@ -107,6 +227,26 @@ class AmesimPnvo001SignalXmlTests(unittest.TestCase):
         self.assertIn("valve_1.xv", result["series"])
         self.assertGreater(result["diagnostics"]["signal"]["propagations"], 0)
 
+    def test_high_pressure_helium_step_restarts_solver_at_event(self) -> None:
+        xml = build_reactflow_system_xml(high_pressure_helium_step_project())
+        result = run_system_xml_simulation(xml)
+
+        self.assertTrue(result["success"], result["message"])
+        self.assertEqual(result["simulatedUntil"], 0.042)
+        self.assertEqual(result["diagnostics"]["signal"]["eventTimes"], [0.04])
+
+        times = result["series"]["time"]
+        before_event = times.index(0.038)
+        at_event = times.index(0.04)
+        self.assertEqual(result["series"]["step_1.out.signal"][before_event], 0.0)
+        self.assertEqual(result["series"]["step_1.out.signal"][at_event], 1.0)
+        self.assertEqual(result["series"]["valve_1.xv"][before_event], 0.0)
+        self.assertEqual(result["series"]["valve_1.xv"][at_event], 1.0)
+        self.assertGreater(
+            result["series"]["valve_1.port_2.m_flow"][at_event],
+            0.45,
+        )
+
 
 if __name__ == "__main__":
     unittest.main()

tests/test_amesim_signal_components.py

@@ -20,6 +20,8 @@ class AmesimSignalComponentTests(unittest.TestCase):
         self.assertEqual(step.output_at(0.49), 0.2)
         self.assertEqual(step.output_at(0.5), 0.8)
         self.assertEqual(step.signal_output_values(0.5), {"out": 0.8})
+        self.assertEqual(step.signal_event_times(0.0, 1.0), (0.5,))
+        self.assertEqual(step.signal_event_times(0.5, 1.0), ())
 
 
     def test_ud00_output_interpolates_piecewise_signal(self) -> None:
@@ -38,6 +40,7 @@ class AmesimSignalComponentTests(unittest.TestCase):
         self.assertAlmostEqual(signal.output_at(2.5), 15.0)
         self.assertAlmostEqual(signal.output_at(5.0), 35.0)
         self.assertEqual(signal.signal_output_values(2.5), {"out": 15.0})
+        self.assertEqual(signal.signal_event_times(0.0, 5.0), (0.5, 1.5, 3.5))
 
     def test_ud00_can_cycle_active_stages(self) -> None:
         signal = AmesimUd00(
@@ -53,6 +56,7 @@ class AmesimSignalComponentTests(unittest.TestCase):
         self.assertAlmostEqual(signal.output_at(0.25), 2.5)
         self.assertAlmostEqual(signal.output_at(1.25), 12.5)
         self.assertAlmostEqual(signal.output_at(2.25), 2.5)
+        self.assertEqual(signal.signal_event_times(0.0, 5.0), (1.0, 2.0, 3.0, 4.0))
 
     def test_ud00_registry_rejects_fractional_stage_controls(self) -> None:
         with self.assertRaisesRegex(ValueError, "nstages must be an integer"):
@@ -91,6 +95,24 @@ class AmesimSignalComponentTests(unittest.TestCase):
         self.assertAlmostEqual(step.out.signal, 0.75)
         self.assertAlmostEqual(valve.res.signal, 0.75)
         self.assertAlmostEqual(valve.opening, 0.75)
+        self.assertEqual(resolver.event_times(0.0, 0.2), (0.1,))
+
+    def test_signal_resolver_event_times_are_sorted_and_deduplicated(self) -> None:
+        network = SimulationNetwork("signal-events")
+        network.add_component(
+            AmesimStep0("step_2", self.medium, initial=0.0, final=1.0, time=0.2)
+        )
+        network.add_component(
+            AmesimStep0("step_1", self.medium, initial=1.0, final=0.0, time=0.1)
+        )
+        network.add_component(
+            AmesimStep0("step_3", self.medium, initial=0.0, final=1.0, time=0.2)
+        )
+
+        resolver = SignalResolver(network)
+
+        self.assertEqual(resolver.event_times(0.0, 0.3), (0.1, 0.2))
+        self.assertEqual(resolver.event_times(0.2, 0.3), ())
 
 
 if __name__ == "__main__":

tests/test_component_catalog.py

@@ -50,6 +50,9 @@ class ComponentCatalogTests(unittest.TestCase):
         self.assertEqual(library["label"], "AMESim 组件库")
         self.assertEqual([category["id"] for category in library["categories"]], ["media", "storage", "flow", "junctions", "boundary", "signals", "mechanical"])
         self.assertEqual(set(components), {"amesim_ideal_air_medium", "amesim_helium_medium", "amesim_pnpl01", "amesim_step0", "amesim_ud00", "amesim_f000", "amesim_forc", "amesim_mecmas21", "amesim_lstp00a", "amesim_lmechn1", "amesim_pnch023", "amesim_pnch012", "amesim_pnor001", "amesim_pnvo001_fixed", "amesim_pnvo001", "amesim_pnl00r", "amesim_pnl0001", "amesim_pnl0002", "amesim_pnl0003", "amesim_pn3node2", "amesim_p4node2"})
+        for model_type, component in components.items():
+            with self.subTest(model_type=model_type):
+                self.assertEqual(component["symbol"], model_type)
         self.assertEqual(
             components["amesim_ideal_air_medium"]["role"],
             "amesimGasMediumDefinition",

tests/test_core_solver.py

@@ -1,3 +1,4 @@
+import math
 import sys
 import types
 import unittest
@@ -78,6 +79,124 @@ class IntegrateOdeTests(unittest.TestCase):
         self.assertEqual(result.status, "cancelled")
         self.assertEqual(result.t, [0.0])
 
+    def test_segmented_bdf_uses_left_limit_and_restarts_at_event(self) -> None:
+        import scipy.integrate
+
+        event_time = 0.5
+        actual_bdf = scipy.integrate.BDF
+        starts: list[float] = []
+        bounds: list[float] = []
+        call_times: list[list[float]] = []
+
+        class RecordingBDF(actual_bdf):
+            def __init__(self, fun, t0, y0, t_bound, **kwargs):
+                starts.append(float(t0))
+                bounds.append(float(t_bound))
+                segment_calls: list[float] = []
+                call_times.append(segment_calls)
+
+                def recording_fun(time, state):
+                    segment_calls.append(float(time))
+                    return fun(time, state)
+
+                super().__init__(recording_fun, t0, y0, t_bound, **kwargs)
+
+        with patch.object(scipy.integrate, "BDF", RecordingBDF):
+            result = integrate_ode(
+                rhs=lambda time, _state: [1.0 if time < event_time else 2.0],
+                initial_state=[0.0],
+                config=SolveIVPConfig(
+                    t_start=0.0,
+                    t_stop=1.0,
+                    method="BDF",
+                    max_step=0.1,
+                    first_step=0.8,
+                ),
+                t_eval=[0.0, event_time, event_time, 1.0],
+                breakpoints=[event_time],
+            )
+
+        self.assertTrue(result.success, result.message)
+        self.assertEqual(starts, [0.0, event_time])
+        self.assertEqual(bounds[0], math.nextafter(event_time, -math.inf))
+        self.assertEqual(bounds[1], 1.0)
+        self.assertTrue(call_times[0])
+        self.assertTrue(all(time < event_time for time in call_times[0]))
+        self.assertTrue(any(time >= event_time for time in call_times[1]))
+        self.assertEqual(result.t, [0.0, event_time, 1.0])
+        self.assertAlmostEqual(result.y[0][-1], 1.5, places=5)
+
+    def test_segmented_implicit_solvers_merge_samples_and_report_progress(self) -> None:
+        event_time = 0.4
+
+        for method in ("BDF", "Radau"):
+            with self.subTest(method=method):
+                callback_times: list[float] = []
+                result = integrate_ode(
+                    rhs=lambda time, _state: [1.0 if time < event_time else 3.0],
+                    initial_state=[0.0],
+                    config=SolveIVPConfig(
+                        t_start=0.0,
+                        t_stop=1.0,
+                        method=method,
+                        max_step=0.05,
+                        first_step=0.9,
+                    ),
+                    t_eval=[0.0, event_time, event_time, 0.7, 1.0],
+                    accepted_step_callback=callback_times.append,
+                    breakpoints=[event_time, event_time],
+                )
+
+                self.assertTrue(result.success, result.message)
+                self.assertEqual(result.t, [0.0, event_time, 0.7, 1.0])
+                self.assertAlmostEqual(result.y[0][-1], 2.2, places=5)
+                self.assertEqual(callback_times.count(event_time), 1)
+                self.assertTrue(
+                    all(
+                        earlier < later
+                        for earlier, later in zip(
+                            callback_times,
+                            callback_times[1:],
+                        )
+                    )
+                )
+
+    def test_segmented_solver_can_cancel_after_crossing_a_breakpoint(self) -> None:
+        callback_times: list[float] = []
+        cancellation_requested = False
+
+        def record_progress(time: float) -> None:
+            nonlocal cancellation_requested
+            callback_times.append(time)
+            cancellation_requested = time >= 0.55
+
+        result = integrate_ode(
+            rhs=lambda _time, _state: [1.0],
+            initial_state=[0.0],
+            config=SolveIVPConfig(
+                t_start=0.0,
+                t_stop=1.0,
+                method="BDF",
+                max_step=0.05,
+            ),
+            t_eval=[0.0, 0.2, 0.4, 0.6, 0.8, 1.0],
+            cancel_check=lambda: cancellation_requested,
+            accepted_step_callback=record_progress,
+            breakpoints=[0.4, 0.8],
+        )
+
+        self.assertFalse(result.success)
+        self.assertEqual(result.status, "cancelled")
+        self.assertIn(0.4, callback_times)
+        self.assertGreater(callback_times[-1], 0.4)
+        self.assertTrue(
+            all(
+                earlier < later
+                for earlier, later in zip(callback_times, callback_times[1:])
+            )
+        )
+        self.assertEqual(result.t, sorted(set(result.t)))
+
 
 if __name__ == "__main__":
     unittest.main()

tests/test_pressure_flow_solver_initialization.py

@@ -0,0 +1,198 @@
+from __future__ import annotations
+
+from types import SimpleNamespace
+import unittest
+from unittest.mock import patch
+
+from app.simulation.components.amesim.boundary.sources import AmesimPnpl01
+from app.simulation.components.amesim.flow.orifices import (
+    AmesimPnvo001SignalOpening,
+)
+from app.simulation.components.amesim.media.mediums import (
+    AmesimHeliumPengRobinsonMedium,
+)
+from app.simulation.components.experimental.storage.cylinder import Cylinder
+from app.simulation.components.experimental.storage.tank import Tank
+from app.simulation.core.medium import IdealGasMedium
+from app.simulation.core.state import VolumeState
+from app.simulation.solvers.algebraic import AlgebraicSolveError, PressureFlowSolver
+from app.simulation.systems.network import SimulationNetwork
+
+
+class PressureFlowSolverInitializationTests(unittest.TestCase):
+    @staticmethod
+    def _near_equal_pressure_network() -> tuple[
+        SimulationNetwork,
+        AmesimHeliumPengRobinsonMedium,
+        Cylinder,
+        Tank,
+        AmesimPnvo001SignalOpening,
+    ]:
+        medium = AmesimHeliumPengRobinsonMedium()
+        high = Cylinder("high", medium, V=0.057, p0=1.0e5, T0=256.1)
+        low = Tank("low", medium, V=0.015, p0=1.0e5, T0=298.2)
+        valve = AmesimPnvo001SignalOpening(
+            "valve",
+            medium,
+            cq=0.45,
+            area0=7.85e-5,
+            gi=1.0,
+            flowset=1.0,
+            opening0=1.0,
+        )
+        valve.res.signal = 1.0
+
+        network = SimulationNetwork("near-equal-pressure")
+        for component in (high, low, valve):
+            network.add_component(component)
+        network.connect("high", "port_b", "valve", "port_2")
+        network.connect("valve", "port_3", "low", "port_a")
+        return network, medium, high, low, valve
+
+    @staticmethod
+    def _set_pressure_temperature(
+        component: Cylinder | Tank,
+        medium: AmesimHeliumPengRobinsonMedium,
+        pressure: float,
+        temperature: float,
+    ) -> None:
+        mass = medium.density(pressure, temperature) * component.V
+        component.state = VolumeState(
+            m=mass,
+            U=mass * medium.specific_internal_energy(temperature),
+        )
+        component.refresh_thermodynamic_ports()
+
+    def test_current_storage_pressure_reseeds_stale_orifice_ports_and_flow(self) -> None:
+        network, medium, high, low, valve = self._near_equal_pressure_network()
+        solver = PressureFlowSolver(network, max_evaluations=10)
+        high_pressure = 10_790_000.0
+
+        self._set_pressure_temperature(high, medium, high_pressure, 256.1)
+        self._set_pressure_temperature(low, medium, high_pressure - 300.0, 298.2)
+        initial = solver.solve()
+        self.assertTrue(initial.success)
+
+        stale_low_pressure = valve.port_3.p
+        stale_flow = valve.port_2.m_flow
+        self._set_pressure_temperature(low, medium, high_pressure - 100.0, 298.2)
+        self.assertNotAlmostEqual(low.port_a.p, stale_low_pressure, places=3)
+
+        updated = solver.solve()
+
+        self.assertTrue(updated.success)
+        self.assertEqual(updated.evaluations, 0)
+        self.assertAlmostEqual(valve.port_2.p, high.port_b.p, places=6)
+        self.assertAlmostEqual(valve.port_3.p, low.port_a.p, places=6)
+        self.assertNotAlmostEqual(valve.port_2.m_flow, stale_flow, places=8)
+        self.assertAlmostEqual(
+            valve.port_2.m_flow,
+            valve.mass_flow(valve.port_2.p, valve.port_3.p),
+            places=10,
+        )
+        self.assertAlmostEqual(high.port_b.m_flow, -valve.port_2.m_flow, places=10)
+        self.assertAlmostEqual(low.port_a.m_flow, -valve.port_3.m_flow, places=10)
+
+    @staticmethod
+    def _closed_boundary_solver() -> PressureFlowSolver:
+        boundary = AmesimPnpl01("closed")
+        boundary.port_1.p = 100_000.0
+        boundary.port_1.m_flow = 1.0
+        network = SimulationNetwork("closed-boundary")
+        network.add_component(boundary)
+        return PressureFlowSolver(network)
+
+    @staticmethod
+    def _least_squares_result(x, *, status: int):
+        return SimpleNamespace(
+            x=x,
+            success=status > 0,
+            status=status,
+            message="test optimizer result",
+            nfev=1,
+        )
+
+    def test_status_zero_is_accepted_only_for_finite_converged_residuals(self) -> None:
+        exact_solver = self._closed_boundary_solver()
+
+        def exact_status_zero(_fun, x0, **_kwargs):
+            values = x0.copy()
+            flow_index = next(
+                index
+                for index, unknown in enumerate(exact_solver.unknowns)
+                if unknown.variable == "m_flow"
+            )
+            values[flow_index] = 0.0
+            return self._least_squares_result(values, status=0)
+
+        with patch.object(
+            PressureFlowSolver,
+            "_seed_explicit_mass_flows",
+            return_value=None,
+        ), patch("scipy.optimize.least_squares", side_effect=exact_status_zero):
+            diagnostics = exact_solver.solve()
+        self.assertTrue(diagnostics.success)
+        self.assertEqual(diagnostics.max_scaled_residual, 0.0)
+
+        inaccurate_solver = self._closed_boundary_solver()
+
+        def inaccurate_status_zero(_fun, x0, **_kwargs):
+            values = x0.copy()
+            flow_index = next(
+                index
+                for index, unknown in enumerate(inaccurate_solver.unknowns)
+                if unknown.variable == "m_flow"
+            )
+            values[flow_index] = 1.0
+            return self._least_squares_result(values, status=0)
+
+        with patch.object(
+            PressureFlowSolver,
+            "_seed_explicit_mass_flows",
+            return_value=None,
+        ), patch("scipy.optimize.least_squares", side_effect=inaccurate_status_zero):
+            with self.assertRaises(AlgebraicSolveError):
+                inaccurate_solver.solve()
+
+        invalid_status_solver = self._closed_boundary_solver()
+
+        def exact_invalid_status(_fun, x0, **_kwargs):
+            values = x0.copy()
+            flow_index = next(
+                index
+                for index, unknown in enumerate(invalid_status_solver.unknowns)
+                if unknown.variable == "m_flow"
+            )
+            values[flow_index] = 0.0
+            return self._least_squares_result(values, status=-1)
+
+        with patch.object(
+            PressureFlowSolver,
+            "_seed_explicit_mass_flows",
+            return_value=None,
+        ), patch("scipy.optimize.least_squares", side_effect=exact_invalid_status):
+            with self.assertRaises(AlgebraicSolveError):
+                invalid_status_solver.solve()
+
+    def test_zero_residual_seed_does_not_bypass_positive_pressure_bound(self) -> None:
+        medium = IdealGasMedium()
+        tank = Tank("tank", medium, V=1.0)
+        plug = AmesimPnpl01("plug")
+        network = SimulationNetwork("invalid-negative-pressure")
+        network.add_component(tank)
+        network.add_component(plug)
+        network.connect("tank", "port_a", "plug", "port_1")
+
+        tank.state = VolumeState(m=1.0, U=-1000.0)
+        tank.refresh_thermodynamic_ports()
+        self.assertLess(tank.port_a.p, 0.0)
+
+        solver = PressureFlowSolver(network, max_evaluations=10)
+        with self.assertRaises(AlgebraicSolveError):
+            solver.solve()
+        self.assertIsNotNone(solver.last_diagnostics)
+        self.assertFalse(solver.last_diagnostics.success)
+
+
+if __name__ == "__main__":
+    unittest.main()