PythonModels/systems/test_mql.py

@@ -3866,6 +3866,17 @@ _PISTON_FORCE_BINDINGS = (
     ("mass_friction_endstops_17", "pn_brp2_15", "p4_port3_far_primary_chamber"),
 )
 
+_ELASTIC_ENDSTOP_FORCE_BINDINGS = (
+    ("mass_friction_endstops_10", "mass_friction_endstops_18", "elasticendstop_8"),
+    ("mass_friction_endstops_11", "mass_friction_endstops_18", "elasticendstop_9"),
+    ("mass_friction_endstops_12", "mass_friction_endstops_18", "elasticendstop_10"),
+    ("mass_friction_endstops_13", "mass_friction_endstops_18", "elasticendstop_11"),
+    ("mass_friction_endstops_14", "mass_friction_endstops_18", "elasticendstop_12"),
+    ("mass_friction_endstops_15", "mass_friction_endstops_18", "elasticendstop_13"),
+    ("mass_friction_endstops_16", "mass_friction_endstops_18", "elasticendstop_14"),
+    ("mass_friction_endstops_17", "mass_friction_endstops_18", "elasticendstop_15"),
+)
+
 
 class TestMqlFullStateClosure:
     def __init__(self, *, pneumatic_closure: object, mechanical_closure: object) -> None:
@@ -3903,15 +3914,23 @@ class TestMqlFullStateClosure:
     def rhs(self, state_vector: list[float]) -> list[float]:
         pneumatic_state, mechanical_state = self._split_state(list(state_vector))
         pneumatic_snapshot = self.pneumatic_closure.snapshot(pneumatic_state)
+        mechanical_snapshot = self.mechanical_closure.snapshot(mechanical_state)
         return [
             *self.pneumatic_closure.rhs(pneumatic_state),
             *self.mechanical_closure.rhs(
                 mechanical_state,
-                force_by_mass_alias=self._piston_force_by_mass_alias(pneumatic_snapshot),
+                force_by_mass_alias=self._force_by_mass_alias(
+                    pneumatic_snapshot,
+                    mechanical_snapshot,
+                ),
             ),
         ]
 
-    def _piston_force_by_mass_alias(self, pneumatic_snapshot: object) -> dict[str, float]:
+    def _force_by_mass_alias(
+        self,
+        pneumatic_snapshot: object,
+        mechanical_snapshot: object,
+    ) -> dict[str, float]:
         from PythonModels.systems.test_mql_pneumatic import pressure_to_amesim_gauge_pa
 
         force_by_mass_alias: dict[str, float] = {}
@@ -3921,6 +3940,22 @@ class TestMqlFullStateClosure:
             force_by_mass_alias[mass_alias] = (
                 pressure_to_amesim_gauge_pa(chamber.p) * piston.annulus_area_m2
             )
+
+        state_by_alias = {state.alias: state for state in mechanical_snapshot.states}
+        for mass_alias, support_mass_alias, endstop_alias in _ELASTIC_ENDSTOP_FORCE_BINDINGS:
+            mass_state = state_by_alias[mass_alias]
+            support_state = state_by_alias[support_mass_alias]
+            endstop = self.mechanical_closure.assembly.elastic_endstops[
+                endstop_alias
+            ].endstop()
+            gap_mm = (support_state.displacement_m - mass_state.displacement_m) * 1.0e3
+            penetration_velocity_m_s = (
+                mass_state.velocity_m_s - support_state.velocity_m_s
+            )
+            force_by_mass_alias[mass_alias] = (
+                force_by_mass_alias.get(mass_alias, 0.0)
+                - endstop.contact_force(gap_mm, penetration_velocity_m_s)
+            )
         return force_by_mass_alias
 
 

tests/test_test_mql_pnl0001_segment.py

@@ -554,6 +554,30 @@ class TestMqlPn3P4NodeChamberSegmentTests(unittest.TestCase):
         )
         self.assertAlmostEqual(rhs[112], -0.8167936695810917)
 
+    def test_full_state_closure_applies_elastic_endstop_force_to_small_masses(self) -> None:
+        closure = self.system.full_state_closure_from_spec(
+            self.spec,
+            inlet_node_pressure_pa=15.31e6,
+            resistance_boundary_pressure_pa=15.29e6,
+        )
+        state = closure.initial_state_vector()
+        state[113] = 1.0e-3
+
+        rhs = closure.rhs(state)
+        initial_rhs = closure.rhs(closure.initial_state_vector())
+        endstop = closure.mechanical_closure.assembly.elastic_endstops[
+            "elasticendstop_8"
+        ].endstop()
+        expected_contact_force = endstop.contact_force(-1.0, 0.0)
+        mass = closure.mechanical_closure.assembly.masses[
+            "mass_friction_endstops_10"
+        ].mass_kg
+
+        self.assertAlmostEqual(
+            rhs[112],
+            initial_rhs[112] - expected_contact_force / mass,
+        )
+
     def test_simulates_full_132_state_closure(self) -> None:
         solution = self.system.simulate_full_state_from_spec(
             self.spec,