New question #674229 on Yade:
https://answers.launchpad.net/yade/+question/674229
Dear all,
I have run a very simple script to prepare a packing with 10,000 particles. But
when this process is finished with unbalancedForce lower than 0.01, I find
there are more than 2,000 particles out of the total 10,000 particles without
any interactions with other particles or walls ('float particles' for which
O.bodies[i.id].intrs()==[]). I wonder if this is normal or there is something
wrong with my simulation. The codes are attached below and thanks for your
consideration.
from yade import pack, qt, plot
import time
import numpy as np
############################################
### DEFINING VARIABLES AND MATERIALS ###
############################################
ts = time.time()
pressure = -1e5
r = 0.005
n = 10000
size0 = 0.3
mn,mx=Vector3(0,0,0),Vector3(size0,size0,size0)
## create materials for spheres and plates
O.materials.append(CohFrictMat(density=2650,young=6e8,poisson=.8,frictionAngle=0.5,isCohesive=True,normalCohesion=5e10,shearCohesion=5e10,momentRotationLaw=False,label='spheres'))
O.materials.append(CohFrictMat(density=0,young=8.8e10,poisson=.8,frictionAngle=0.,isCohesive=False,label='walls'))
## create walls around the packing
walls=aabbWalls([mn,mx],thickness=0,material='walls')
wallIds=O.bodies.append(walls)
## use a SpherePack object to generate a random loose particles packing
sp=pack.SpherePack()
sp.makeCloud(mn,mx,rMean=r,rRelFuzz=0.4,periodic=False,num=n,seed=1)
sp.toSimulation(material='spheres')
print(len(O.bodies))
############################
### DEFINING ENGINES ###
############################
triax=TriaxialStressController(
## TriaxialStressController will be used to control stress and strain.
It controls particles size and plates positions.
## this control of boundary conditions was used for instance in
http://dx.doi.org/10.1016/j.ijengsci.2008.07.002
#maxMultiplier=1.+2e4/young, # spheres growing factor (fast growth)
#finalMaxMultiplier=1.+2e3/young, # spheres growing factor (slow growth)
thickness = 0,
## switch stress/strain control using a bitmask. What is a bitmask,
huh?!
## Say x=1 if stess is controlled on x, else x=0. Same for for y and z,
which are 1 or 0.
## Then an integer uniquely defining the combination of all these tests
is: mask = x*1 + y*2 + z*4
## to put it differently, the mask is the integer whose binary
representation is xyz, i.e.
## "100" (1) means "x", "110" (3) means "x and y", "111" (7) means "x
and y and z", etc.
stressMask = 7,
internalCompaction=False, # If true the confining pressure is generated
by growing particles
goal1 = pressure,
goal2 = pressure,
goal3 = pressure,
max_vel = 1,
)
newton=NewtonIntegrator(gravity=(0,0,0), damping=.1)
O.engines=[
ForceResetter(),
InsertionSortCollider([Bo1_Sphere_Aabb(),Bo1_Box_Aabb()]),
InteractionLoop(
[Ig2_Sphere_Sphere_ScGeom6D(),Ig2_Box_Sphere_ScGeom6D(),],
[Ip2_CohFrictMat_CohFrictMat_CohFrictPhys(setCohesionOnNewContacts=False,label='cohesiveIp'),],
[Law2_ScGeom6D_CohFrictPhys_CohesionMoment(),]
),
## We will use the global stiffness of each body to determine an
optimal timestep (see
https://yade-dem.org/w/images/1/1b/Chareyre&Villard2005_licensed.pdf)
GlobalStiffnessTimeStepper(active=1,timeStepUpdateInterval=100,timestepSafetyCoefficient=0.8),
triax,
#TriaxialStateRecorder(iterPeriod=100,file='WallStresses'+table.key),
newton,
PyRunner(command='addPlotData()',iterPeriod=1000),
PyRunner(command='check()',iterPeriod=1000),
PyRunner(command='savePack()',iterPeriod=1000),
]
def addPlotData():
pp = utils.porosity() #this is the porosity of the cell.
ee = pp / (1-pp) #this is the void ratio of the 3D cell.
a = [i for i in O.bodies if i.intrs()==[]]
plot.addData(unbalanced=unbalancedForce(),i=O.iter,
s11 = -getStress()[0,0],
s22 = -getStress()[1,1],
s33 = -getStress()[2,2],
void = ee,
Num = len(a)
)
plot.plots={'i':('unbalanced',),'i ':('s11','s22','s33'),
' i ':('void',),' i':('Num')
}
# show the plot
plot.plot()
yade.qt.Controller(), yade.qt.View()
def savePack():
O.save('packing_100kPa_Tmp.yade.gz')
def check():
unb=unbalancedForce()
if unb<0.01 and abs(pressure-triax.meanStress)/-pressure<0.001:
print('Packing generated!')
print('time: '+str((time.time()-ts)/60.)+'min')
O.save('packing_100kPa.yade.gz')
O.pause()
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