From d66f290e474ff6ed09381a7ddcaae1e51997979a Mon Sep 17 00:00:00 2001
From: Rafael Ravedutti <rafaelravedutti@gmail.com>
Date: Thu, 12 Oct 2023 00:36:43 +0200
Subject: [PATCH] Include torque contribution
Signed-off-by: Rafael Ravedutti <rafaelravedutti@gmail.com>
---
examples/dem.py | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)
diff --git a/examples/dem.py b/examples/dem.py
index 53adec1..339dee7 100644
--- a/examples/dem.py
+++ b/examples/dem.py
@@ -4,7 +4,8 @@ import sys
def linear_spring_dashpot(i, j):
- skip_when(penetration_depth(i, j) >= 0.0)
+ delta_ij = -penetration_depth
+ skip_when(delta_ij < 0.0)
velocity_wf_i = linear_velocity[i] + cross(angular_velocity[i], contact_point(i, j) - position[i])
velocity_wf_j = linear_velocity[j] + cross(angular_velocity[j], contact_point(i, j) - position[j])
@@ -12,7 +13,7 @@ def linear_spring_dashpot(i, j):
rel_vel = -velocity_wf_i - velocity_wf_j
rel_vel_n = dot(rel_vel, contact_normal(i, j)) * contact_normal(i, j)
rel_vel_t = rel_vel - rel_vel_n
- fN = stiffness_norm[i, j] * (-penetration_depth(i, j)) * contact_normal(i, j) + damping_norm[i, j] * rel_vel_n;
+ fN = stiffness_norm[i, j] * delta_ij * contact_normal(i, j) + damping_norm[i, j] * rel_vel_n;
tan_spring_disp = tangential_spring_displacement[i, j]
impact_vel_magnitude = impact_velocity_magnitude[i, j]
@@ -49,7 +50,11 @@ def linear_spring_dashpot(i, j):
fTabs = min(fTLS_len, f_friction_abs)
fT = fTabs * t
- force[i] += fN + fT
+ partial_force = fN + fT
+ partial_torque = cross(contact_point(i, j) - position[i], partial_force)
+
+ force[i] += partial_force
+ torque[i] += partial_torque
def euler(i):
@@ -132,6 +137,7 @@ psim.add_property('mass', pairs.double(), 1.0)
psim.add_property('linear_velocity', pairs.vector())
psim.add_property('angular_velocity', pairs.vector())
psim.add_property('force', pairs.vector(), volatile=True)
+psim.add_property('torque', pairs.vector(), volatile=True)
psim.add_property('radius', pairs.double(), 1.0)
psim.add_property('normal', pairs.vector())
psim.add_feature('type', ntypes)
--
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