Merge pull request #172 from bhosale2/171_update_internal_damping_rod…

…_rigid_body update: Damping values for rod-rigid body contact cases (#171)
GazzolaLab · Aug 10, 2022 · 67c3b9e · 67c3b9e
2 parents c0b0b27 + 4974ba1
commit 67c3b9e
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Showing 4 changed files with 45 additions and 17 deletions.
diff --git a/examples/RigidBodyCases/RodRigidBodyContact/rod_cylinder_contact.py b/examples/RigidBodyCases/RodRigidBodyContact/rod_cylinder_contact.py
@@ -5,15 +5,15 @@
 
 def rod_cylinder_contact_case(inclination_angle=0.0):
     class RodCylinderParallelContact(
-        BaseSystemCollection, Constraints, Connections, CallBacks, Forcing
+        BaseSystemCollection, Constraints, Connections, CallBacks, Forcing, Damping
     ):
         pass
 
     rod_cylinder_parallel_contact_simulator = RodCylinderParallelContact()
 
     # time step etc
     final_time = 10.0
-    time_step = 1e-4
+    time_step = 5e-4
     total_steps = int(final_time / time_step) + 1
     rendering_fps = 30  # 20 * 1e1
     step_skip = int(1.0 / (rendering_fps * time_step))
@@ -25,7 +25,6 @@ class RodCylinderParallelContact(
     poisson_ratio = 0.5
     shear_modulus = E / (2 * (1 + poisson_ratio))
     n_elem = 50
-    nu = 0.5
     start = np.zeros((3,))
     direction = np.array([np.sin(inclination_angle), 0.0, np.cos(inclination_angle)])
     normal = np.array([0.0, 1.0, 0.0])
@@ -38,7 +37,7 @@ class RodCylinderParallelContact(
         base_length,
         base_radius,
         density,
-        nu,
+        0.0,  # internal damping constant, deprecated in v0.3.0
         E,
         shear_modulus=shear_modulus,
     )
@@ -70,6 +69,14 @@ class RodCylinderParallelContact(
         nu=0.1,
     )
 
+    # add damping
+    damping_constant = 1e-2
+    rod_cylinder_parallel_contact_simulator.dampen(rod).using(
+        AnalyticalLinearDamper,
+        damping_constant=damping_constant,
+        time_step=time_step,
+    )
+
     # Add callbacks
     post_processing_dict_list = []
     # For rod

diff --git a/examples/RigidBodyCases/RodRigidBodyContact/rod_cylinder_contact_friction.py b/examples/RigidBodyCases/RodRigidBodyContact/rod_cylinder_contact_friction.py
@@ -7,15 +7,15 @@ def rod_cylinder_contact_friction_case(
     force_coefficient=0.1, normal_force_mag=10, POST_PROCESSING=False
 ):
     class RodCylinderParallelContact(
-        BaseSystemCollection, Constraints, Connections, CallBacks, Forcing
+        BaseSystemCollection, Constraints, Connections, CallBacks, Forcing, Damping
     ):
         pass
 
     rod_cylinder_parallel_contact_simulator = RodCylinderParallelContact()
 
     # time step etc
-    final_time = 20.0
-    time_step = 1e-4
+    final_time = 10.0
+    time_step = 5e-4
     total_steps = int(final_time / time_step) + 1
     rendering_fps = 30  # 20 * 1e1
     step_skip = int(1.0 / (rendering_fps * time_step))
@@ -27,7 +27,6 @@ class RodCylinderParallelContact(
     poisson_ratio = 0.5
     shear_modulus = E / (2 * (1 + poisson_ratio))
     n_elem = 50
-    nu = 0.5
     start = np.zeros((3,))
     direction = np.array([0, 0.0, 1.0])
     normal = np.array([0.0, 1.0, 0.0])
@@ -40,7 +39,7 @@ class RodCylinderParallelContact(
         base_length,
         base_radius,
         density,
-        nu,
+        0.0,  # internal damping constant, deprecated in v0.3.0
         E,
         shear_modulus=shear_modulus,
     )
@@ -57,6 +56,14 @@ class RodCylinderParallelContact(
         UniformForces, force=normal_force_mag * force_coefficient, direction=direction
     )
 
+    # add damping
+    damping_constant = 2e-3
+    rod_cylinder_parallel_contact_simulator.dampen(rod).using(
+        AnalyticalLinearDamper,
+        damping_constant=damping_constant,
+        time_step=time_step,
+    )
+
     cylinder_height = 8 * base_length
     cylinder_radius = base_radius
 

diff --git a/examples/RigidBodyCases/RodRigidBodyContact/rod_cylinder_contact_validation.py b/examples/RigidBodyCases/RodRigidBodyContact/rod_cylinder_contact_validation.py
@@ -4,7 +4,7 @@
 
 
 class SingleRodSingleCylinderInteractionSimulator(
-    BaseSystemCollection, Constraints, Connections, Forcing, CallBacks
+    BaseSystemCollection, Constraints, Connections, Forcing, CallBacks, Damping
 ):
     pass
 
@@ -51,7 +51,6 @@ class SingleRodSingleCylinderInteractionSimulator(
 base_radius = 0.01
 base_area = np.pi * base_radius ** 2
 density = 1750
-nu = 0.001
 E = 3e5
 poisson_ratio = 0.5
 shear_modulus = E / (1 + poisson_ratio)
@@ -87,7 +86,7 @@ class SingleRodSingleCylinderInteractionSimulator(
     base_length,
     base_radius,
     density,
-    nu,
+    0.0,  # internal damping constant, deprecated in v0.3.0
     E,
     shear_modulus=shear_modulus,
 )
@@ -138,11 +137,19 @@ def make_callback(self, system, time, current_step: int):
     PositionCollector, step_skip=200, callback_params=recorded_cyl_history
 )
 
+# add damping
+damping_constant = 1e-3
+dt = 1e-4
+single_rod_sim.dampen(rod1).using(
+    AnalyticalLinearDamper,
+    damping_constant=damping_constant,
+    time_step=dt,
+)
+
 single_rod_sim.finalize()
 timestepper = PositionVerlet()
 final_time = 2.0
 dl = base_length / n_elem
-dt = 1e-4
 total_steps = int(final_time / dt)
 print("Total steps", total_steps)
 

diff --git a/examples/RigidBodyCases/RodRigidBodyContact/rod_cylinder_contact_with_y_normal.py b/examples/RigidBodyCases/RodRigidBodyContact/rod_cylinder_contact_with_y_normal.py
@@ -4,7 +4,7 @@
 
 
 class SingleRodSingleCylinderInteractionSimulator(
-    BaseSystemCollection, Constraints, Connections, Forcing, CallBacks
+    BaseSystemCollection, Constraints, Connections, Forcing, CallBacks, Damping
 ):
     pass
 
@@ -24,7 +24,6 @@ class SingleRodSingleCylinderInteractionSimulator(
 base_radius = 0.01
 base_area = np.pi * base_radius ** 2
 density = 1750
-nu = 0.001
 E = 3e5
 poisson_ratio = 0.5
 shear_modulus = E / (1 + poisson_ratio)
@@ -65,7 +64,7 @@ class SingleRodSingleCylinderInteractionSimulator(
     base_length,
     base_radius,
     density,
-    nu,
+    0.0,  # internal damping constant, deprecated in v0.3.0
     E,
     shear_modulus=shear_modulus,
 )
@@ -116,11 +115,19 @@ def make_callback(self, system, time, current_step: int):
     PositionCollector, step_skip=200, callback_params=recorded_cyl_history
 )
 
+# add damping
+damping_constant = 1e-3
+dt = 1e-4
+single_rod_sim.dampen(rod1).using(
+    AnalyticalLinearDamper,
+    damping_constant=damping_constant,
+    time_step=dt,
+)
+
 single_rod_sim.finalize()
 timestepper = PositionVerlet()
 final_time = 2.0
 dl = base_length / n_elem
-dt = 1e-4
 total_steps = int(final_time / dt)
 print("Total steps", total_steps)