yade-users team mailing list archive

[Seti <question665857@xxxxxxxxxxxxxxxxxxxxx>]

New question #665857 on Yade:
https://answers.launchpad.net/yade/+question/665857

Hi all,

I have done minor changes on CPM script - as per below : 

I have below  question: 
1- Why there is very limited range to change SigmaT inorder to run the script e.g. (1e1-1e4 )if I put 1e5 which is not a very big value for my material it wont run -
2- even when I run it in notifited range after couple of hours I face with below error - can you please help me to fix it? 
ZeroDivisionError                         Traceback (most recent call last)
/usr/bin/yadedaily in <module>()

/usr/bin/yadedaily in stopIfDamaged()
    199                         print "Damaged, stopping."
    200                         ft,fc=max(sigma),min(sigma)
--> 201                         print 'Strengths fc=%g, ft=%g, |fc/ft|=%g'%(fc,ft,abs(fc/ft))
    202                         title=O.tags['sigmaT=3.5e6, compression'] if 'sigmaT=3.5e6, compression' in O.tags.keys() else O.tags['params']
    203                         print 'gnuplot',plot.saveGnuplot(O.tags['id'],title=title)

ZeroDivisionError: float division by zero
Damaged, stopping.

3- how I can track the crack in this script - I want to see changing the crack patern by changing material properties.


Below is script: 
#!/usr/bin/python
# -*- coding: utf-8 -*-
from __future__ import division

from yade import plot,pack,timing, qt
import time, sys, os, copy

#import matplotlib
#matplotlib.rc('text',usetex=True)
#matplotlib.rc('text.latex',preamble=r'\usepackage{concrete}\usepackage{euler}')



"""
A fairly complex script performing uniaxial tension-compression test on hyperboloid-shaped specimen.
Most parameters of the model (and of the setup) can be read from table using yade-multi.
After the simulation setup, tension loading is run and stresses are periodically saved for plotting
as well as checked for getting below the maximum value so far. This indicates failure (see stopIfDamaged
function). After failure in tension, the original setup is loaded anew and the sense of loading reversed.
After failure in compression, strain-stress curves are saved via plot.saveGnuplot and we exit,
giving some useful information like peak stresses in tension/compression.
Running this script for the first time can take long time, as the specimen is prepared using triaxial
compression. Next time, however, an attempt is made to load previously-generated packing 
(from /tmp/triaxPackCache.sqlite) and this expensive procedure is avoided.
The specimen length can be specified, its diameter is half of the length and skirt of the hyperboloid is 
4/5 of the width.
The particle size is constant and can be specified using the sphereRadius parameter.
The 3d display has displacement scaling applied, so that the fracture looks more spectacular. The scale
is 1000 for tension and 100 for compression.
"""



# default parameters or from table
readParamsFromTable(noTableOk=True, # unknownOk=True,
	young=70e7,
	poisson=.2,

	sigmaT=1.1e2,
	frictionAngle=atan(.3),
	epsCrackOnset=1e-4,
	relDuctility=5,

	intRadius=1.5,
	dtSafety=.8,
	damping=0.4,
	strainRateTension=.00001,
	strainRateCompression=.00001,
	setSpeeds=True,
	# 1=tension, 2=compression (ANDed; 3=both)
	doModes=2,

	specimenLength=.15,
	sphereRadius=3.5e-3,

	# isotropic confinement (should be negative)
	isoPrestress=0,
)

from yade.params.table import *

if 'sigmaT=3.5e6, compression' in O.tags.keys(): O.tags['id']=O.tags['id']+O.tags['sigmaT=3.5e6, compression']


# make geom; the dimensions are hard-coded here; could be in param table if desired
# z-oriented hyperboloid, length 20cm, diameter 10cm, skirt 8cm
# using spheres 7mm of diameter

#####################

mat1=CpmMat(young=young,frictionAngle=frictionAngle,poisson=poisson,density=4800,sigmaT=sigmaT,relDuctility=relDuctility,epsCrackOnset=epsCrackOnset,isoPrestress=isoPrestress)

concreteId1=O.materials.append(mat1)

#sp=pack.randomDensePack(pack.inHyperboloid((0,0,-.5*specimenLength),(0,0,.5*specimenLength),.25*specimenLength,.17*specimenLength),spheresInCell=2000,radius=sphereRadius,memoizeDb='/tmp/triaxPackCache.sqlite',returnSpherePack=True)

#############################
sp=pack.SpherePack()
pred=pack.inCylinder((0,0,0.0002),(0,0,0.3),0.05)
O.bodies.append(pack.randomDensePack(pred,radius=0.007))
#pred=pack.inCylinder((0,0,0),(0,0,0.03),0.005)
#O.bodies.append(pack.randomDensePack(pred,radius=0.0005))


#pred=pack.inCylinder((0,0,0),(0,0,0.2),0.1)

#sp=pack.randomDensePack(pred,radius=0.002,material=concreteId)
#O.bodies.append(TS1)
##############

#sp=pack.randomDensePack(pack.inAlignedBox((-.25*specimenLength,-.25*specimenLength,-.5*specimenLength),(.25*specimenLength,.25*specimenLength,.5*specimenLength)),spheresInCell=2000,radius=sphereRadius,memoizeDb='/tmp/triaxPackCache.sqlite',returnSpherePack=True)




#######################


###############
sp.toSimulation()


########################
bb=uniaxialTestFeatures()
negIds,posIds,axis,crossSectionArea=bb['negIds'],bb['posIds'],bb['axis'],bb['area']
O.dt=dtSafety*PWaveTimeStep()
print 'Number of elements: ', len(O.bodies)
#print 'Timestep',O.dt
print 'sigmaT:1.1e2,0.50000, compression'
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_CpmMat_CpmMat_CpmPhys()],
		[Law2_ScGeom_CpmPhys_Cpm()],
	),
	NewtonIntegrator(damping=damping,label='damper'),
	#CpmStateUpdater(realPeriod=.5),
	UniaxialStrainer(strainRate=strainRateTension,axis=axis,asymmetry=0,posIds=posIds,negIds=negIds,crossSectionArea=crossSectionArea,blockDisplacements=False,blockRotations=False,setSpeeds=setSpeeds,label='strainer'),
	PyRunner(virtPeriod=1e-6/strainRateTension,realPeriod=1,command='addPlotData()',label='plotDataCollector',initRun=True),
	PyRunner(realPeriod=4,command='stopIfDamaged()',label='damageChecker'),
	#VTKRecorder(fileName='20d-vtk-ucs-7-',recorders=['all', 'spheres', 'velocity', 'facets', 'boxes', 'color', 'stress', 'cpm', 'wpm', 'intr', 'id', 'jcfpm', 'cracks','bstresses'],iterPeriod=1000),
	#qt.SnapshotEngine(fileBase='3d-ucs-7-',iterPeriod=200,label='snapshot'),

	
]
#O.miscParams=[Gl1_CpmPhys(dmgLabel=False,colorStrain=False,epsNLabel=False,epsT=False,epsTAxes=False,normal=False,contactLine=True)]
#qt.View()
# plot stresses in ¼, ½ and ¾ if desired as well; too crowded in the graph that includes confinement, though
plot.plots={'eps':('sigma')} #,'sigma.50')},'t':('eps')} #'sigma.25','sigma.50','sigma.75')}

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('/tmp/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['sigmaT=3.5e6, compression'] if 'sigmaT=3.5e6, compression' in O.tags.keys() else O.tags['params']
			print 'gnuplot',plot.saveGnuplot(O.tags['id'],title=title)
			print 'Bye.'
                        #print 'sigmaT=MatchMaker(matches=((concreteId1,concreteId1,1.1e9),(concreteId1,concreteId2,1.1e9),(concreteId2,concreteId2,1.1e3))),0.50000, compression'
			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()
waitIfBatch()
O.run(5000,True)
plot.plots={'eps':('sigma')}
plot.plot(subPlots=False)
plot.saveDataTxt('sigmaTttt=1.1e4,0.50000, compression')


#####  PLAY THE SIMULATION HERE WITH "PLAY" BUTTON OR WITH THE COMMAND O.run(N)  #####

rr=yade.qt.Renderer()
rr.shape=False
rr.intrPhys=True


Thanks
Seti



-- 
You received this question notification because your team yade-users is
an answer contact for Yade.