Question #670838 on Yade changed:
https://answers.launchpad.net/yade/+question/670838
Justin requested more information:
Bruno,
I have a similar issue. Please see my MWE below.
When I remove all BC's from "other_nodes" (root_nodes stay fixed) in the
function turnonstuds, my two cylinders explode. Do you know the cause?
Thanks,
Justin
#!/usr/bin/python
# -*- coding: utf-8 -*-
import sys
from yade.gridpfacet import *
import numpy as np
from yade import utils, pack
from yade import ymport
import time,math,random
from yade import qt
qt.View()
root_nodes=[]
other_nodes=[]
spheres_fall = 5
All_steps =54817+spheres_fall
class YadePythonSimulation():
blen = 0.21230 ## Length of Ball pit
O.materials.append(CohFrictMat(young=3e9,density=1e1,poisson=.3,frictionAngle=10,normalCohesion=1e7,shearCohesion=1e7,momentRotationLaw=True,label='grass'))
rCyl = (0.00635+0.003175)/4 ## Lump with of "grass" on back is 1/4 X
1/8
nL = 3 ## Number of spheres, No exact Number here, just trial
and error
L = .022 ## Height of spheres after leveling
## Time step set to 20% of Rayleigh Wave
O.dt=0.0020719234774279633
## Engines
O.engines=[
###Reset all forces stored in Scene::forces (O.forces in
python). Typically, this is the first engine to be run at every step.
In addition, reset those energies that should be reset, if energy tracing is
enabled.
## Resets forces and moments that act on bodies
ForceResetter(),
## Using bounding boxes find possible body collisions.
InsertionSortCollider([
Bo1_Sphere_Aabb(),
Bo1_Facet_Aabb(),
Bo1_GridConnection_Aabb(),
Bo1_Box_Aabb(),
# Bo1_GridConnection_Aabb(),
]),
InteractionLoop([
# Ig2_GridConnection_GridConnection_GridCoGridCoGeom(),
# Ig2_GridNode_GridNode_GridNodeGeom6D(),
# Ig2_Sphere_GridConnection_ScGridCoGeom(),
Ig2_Facet_Sphere_ScGeom(),
Ig2_Sphere_Sphere_ScGeom(),
Ig2_Box_Sphere_ScGeom(),
Ig2_GridNode_GridNode_GridNodeGeom6D(),
Ig2_Sphere_GridConnection_ScGridCoGeom(),
Ig2_GridConnection_GridConnection_GridCoGridCoGeom(),
],
[
Ip2_CohFrictMat_CohFrictMat_CohFrictPhys(setCohesionNow=True,setCohesionOnNewContacts=False),
# internal cylinder physics
Ip2_FrictMat_FrictMat_FrictPhys() # physics for external
interactions, i.e., cylinder-cylinder, sphere-sphere, cylinder-sphere
],
[
# Law2_GridCoGridCoGeom_FrictPhys_CundallStrack(),
Law2_ScGridCoGeom_CohFrictPhys_CundallStrack(),
Law2_ScGeom_FrictPhys_CundallStrack(), # contact law
for sphere-sphere
Law2_ScGridCoGeom_FrictPhys_CundallStrack(), # contact law
for cylinder-sphere
Law2_ScGeom6D_CohFrictPhys_CohesionMoment(), # contact law
for "internal" cylinder forces
Law2_GridCoGridCoGeom_FrictPhys_CundallStrack() # contact law
for cylinder-cylinder interaction
]),
NewtonIntegrator(damping=.2,gravity=[0,-9.81,
0],label='newtonInt'),
PyRunner(command='turnonstuds()',iterPeriod=spheres_fall, nDo =
11, label='switchstuds', dead = False),
]
### Create all nodes first :
idxc = -1
x_gap = 0.09 ## tmp
z_gap = 0.1905 ## tmp
range_x = int(math.floor(blen/x_gap)) ## finding the range for x
range_z = int(math.floor(blen/z_gap)) ## finding the range for z
cen_z = -(range_z/2)*z_gap ## Allows the "box" of grass to be center
in Z
tmpi = 0.0
for ii in range(0,range_z):
cen_x = -(range_x/2)*x_gap # Allows the "box" of grass to be
center in X
for jj in range(0,range_x):
for i in np.linspace(0,L,nL):
if i != 0.0:
other_nodes.append(O.bodies.append(gridNode([cen_x,i,cen_z],rCyl,wire=False,fixed=True,material='grass')))
if tmpi == 0.0:
O.bodies.append(gridConnection(root_nodes[-1], other_nodes[-1], rCyl))
else:
O.bodies.append(gridConnection(other_nodes[-2], other_nodes[-1], rCyl))
print(i, "other", cen_x, "x", cen_z,
"z")
elif i == 0.0:
root_nodes.append(O.bodies.append(gridNode([cen_x,i,cen_z],rCyl,wire=False,fixed=True,material='grass')))
tmpi = i
idxc += 1
d = idxc*nL ## Start of grass fiber
cen_x += x_gap
cen_z += z_gap
def run(self):
iterToRun=spheres_fall
O.run(iterToRun, True)
def turnonstuds():
### Turning off BC's to non-rooted nodes
for kk in range(0,len(root_nodes)):
O.bodies[other_nodes[kk]].state.blockedDOFs=''
if __name__ == "__main__":
yaPySi = YadePythonSimulation()
sim1 = yaPySi.run()
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