New question #676639 on Yade:
https://answers.launchpad.net/yade/+question/676639
Hi to all,
currently i am trying to perform simulation of UCS and TS as in the paper <<A
DEM model for soft and hard rocks: Role of grain interlocking on strength >> of
Luc Scholtes and Frédéric-Victor Donzé.
I took the file from trunk/examples/concrete/uniax.py and change the model from
CpmMat to JCFpmMat.
Also i took the microparameters from table 2 in the above paper and put it in
my script.
Some Remarks i saw in my simulation:
As i put intRadius=1 as in table 2, my Coordination number is 3.37 byt in paper
is 6.1
Number of elements: 17412
And Fc = 1.36e06 .
Am i doing something wrong?
Please have a look in my code :
#!/usr/bin/python
# -*- coding: utf-8 -*-
from __future__ import division
from yade import plot,pack,timing
import time, sys, os, copy
#import matplotlib
#matplotlib.rc('text',usetex=True)
# default parameters or from table
readParamsFromTable(noTableOk=True, # unknownOk=True,
density=2640,
young=230e9,
poisson=2.5,
frictionAngle=25,
tensileStrength=22e6,
cohesion=220e6, #10*tensileStrength,
sphereRadius=1.25e-3,
rRelFuzz=0.34,
intRadius=1,
dtSafety=.8,
damping=0.6,
strainRateTension=.05,
strainRateCompression=.5,
setSpeeds=True,
# 1=tension, 2=compression (ANDed; 3=both)
doModes=2,
# isotropic confinement (should be negative)
isoPrestress=0,
)
from yade.params.table import *
if 'description' in O.tags.keys():
O.tags['id']=O.tags['id']+O.tags['description']
sample = O.materials.append(JCFpmMat(young=young, poisson=poisson,
frictionAngle=radians(frictionAngle), cohesion=cohesion,
tensileStrength=tensileStrength,density = density, label='spheres'))
sps=SpherePack()
sp=pack.randomDensePack(pack.inAlignedBox((-25e-3,-25e-3,-62.5e-3),(25e-3,25e-3,62.5e-3)),spheresInCell=2000,radius=sphereRadius,rRelFuzz=rRelFuzz,memoizeDb=False,returnSpherePack=True)
#'/tmp/triaxPackCache.sqlite'
sp.toSimulation(color=(1.09,1.0,0.0),material=sample) #color=(1.09,1.0,0.0)
bb=uniaxialTestFeatures()
negIds,posIds,axis,crossSectionArea=bb['negIds'],bb['posIds'],bb['axis'],bb['area']
O.dt=dtSafety*PWaveTimeStep()
print 'Timestep',O.dt
mm,mx=[pt[axis] for pt in aabbExtrema()]
coord_25,coord_50,coord_75=mm+.25*(mx-mm),mm+.5*(mx-mm),mm+.75*(mx-mm)
area_25,area_50,area_75=approxSectionArea(coord_25,axis),approxSectionArea(coord_50,axis),approxSectionArea(coord_75,axis)
O.engines=[
ForceResetter(),
InsertionSortCollider([Bo1_Sphere_Aabb(aabbEnlargeFactor=intRadius,label='is2aabb')],verletDist=.05*sphereRadius),
InteractionLoop(
[Ig2_Sphere_Sphere_ScGeom(interactionDetectionFactor=intRadius,label='ss2sc')],
[Ip2_JCFpmMat_JCFpmMat_JCFpmPhys(cohesiveTresholdIteration=1)],
[Law2_ScGeom_JCFpmPhys_JointedCohesiveFrictionalPM(Key='cracks',recordCracks=True,cracksFileExist=True,label='interactionLaw')],
),
GlobalStiffnessTimeStepper(active=1,timeStepUpdateInterval=100,timestepSafetyCoefficient=0.8),
UniaxialStrainer(strainRate=strainRateTension,axis=axis,asymmetry=0,posIds=posIds,negIds=negIds,crossSectionArea=crossSectionArea,blockDisplacements=False,blockRotations=False,setSpeeds=setSpeeds,label='strainer'),
NewtonIntegrator(damping=damping,label='damper'),
VTKRecorder(fileName='3d-vtk-',recorders=['intr','cracks','jcfpm','facets','spheres','colors'],Key='cracks',
realPeriod=50),
PyRunner(virtPeriod=1e-6/strainRateTension,realPeriod=1,command='addPlotData()',label='plotDataCollector',initRun=True),
PyRunner(realPeriod=4,command='stopIfDamaged()',label='damageChecker'),
]
plot.plots={'eps':('sigma',)}
O.saveTmp('initial');
O.timingEnabled=False
global mode
mode='tension' if doModes & 1 else 'compression'
def initTest():
global mode
print "init"
if O.iter>0:
O.wait();
O.loadTmp('initial')
print "Reversing plot data"; plot.reverseData()
else: plot.plot(subPlots=False)
strainer.strainRate=abs(strainRateTension) if mode=='tension' else
-abs(strainRateCompression)
try:
from yade import qt
renderer=qt.Renderer()
renderer.dispScale=(1000,1000,1000) if mode=='tension' else
(100,100,100)
except ImportError: pass
print "init done, will now run."
O.step(); # to create initial contacts
# now reset the interaction radius and go ahead
ss2sc.interactionDetectionFactor=1.
is2aabb.aabbEnlargeFactor=1.
O.run()
def stopIfDamaged():
global mode
if O.iter<2 or not plot.data.has_key('sigma'): return # do nothing at
the very beginning
sigma,eps=plot.data['sigma'],plot.data['eps']
extremum=max(sigma) if (strainer.strainRate>0) else min(sigma)
minMaxRatio=0.5 if mode=='tension' else 0.5
if extremum==0: return
import sys; sys.stdout.flush()
if abs(sigma[-1]/extremum)<minMaxRatio or abs(strainer.strain)>(5e-3 if
isoPrestress==0 else 5e-2):
if mode=='tension' and doModes & 2: # only if compression is
enabled
mode='compression'
O.save('uniax-tension.yade.gz')
print "Saved /tmp/uniax-tension.yade.gz (for use with
interaction-histogram.py and uniax-post.py)"
print "Damaged, switching to compression... "; O.pause()
# important! initTest must be launched in a separate
thread;
# otherwise O.load would wait for the iteration to
finish,
# but it would wait for initTest to return and deadlock
would result
import thread; thread.start_new_thread(initTest,())
return
else:
print "Damaged, stopping."
ft,fc=max(sigma),min(sigma)
print 'Strengths fc=%g, ft=%g,
|fc/ft|=%g'%(fc,ft,abs(fc/ft))
title=O.tags['description'] if 'description' in
O.tags.keys() else O.tags['params']
print
'gnuplot',plot.saveGnuplot(O.tags['id'],title=title)
print 'Bye.'
O.pause()
#sys.exit(0) # results in some threading exception
def addPlotData():
yade.plot.addData({'t':O.time,'i':O.iter,'eps':strainer.strain,'sigma':strainer.avgStress+isoPrestress,
'sigma.25':forcesOnCoordPlane(coord_25,axis)[axis]/area_25+isoPrestress,
'sigma.50':forcesOnCoordPlane(coord_50,axis)[axis]/area_50+isoPrestress,
'sigma.75':forcesOnCoordPlane(coord_75,axis)[axis]/area_75+isoPrestress,
})
plot.plot(subPlots=False)
#O.run()
initTest()
Thank You!!
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