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[Ziyu Wang <question702277@xxxxxxxxxxxxxxxxxxxxx>]

New question #702277 on Yade:
https://answers.launchpad.net/yade/+question/702277

Hi,
I want to study the mechanical properties of granite under triaxial compression (under THM coupling).

At present, I have been using JCFpmMat material for simulation. Uniaxial compression and calibration parameters are very successful. However, in triaxial compression, I have been unable to get the failure stage (that is, the stress after the peak does not decrease significantly, but remains at a high value fluctuation).It makes me confused.

Can I use CohFrictmat to achieve my goal? If so, I know too little about CohFrictmat. Is there any paper recommended?

Thanks for help! I will attach my JCFpmMat triaxial compression script,maybe some error happened?

################
from yade import pack, ymport, plot, utils, export, timing
import numpy as np
import sys

#readParamsFromTable(Wy=-30e6)
#from yade.params import table
global Wy
Wy=-30e6
rate=-0.2
damp=0.4
stabilityThreshold=0.001
key='_triax_base_'
young=104e9
name='JCFPM_triax'
#targetPorosity=0.43
compFricDegree=30
poisson=0.4
OUT=str(Wy)+'_JCFPM_triax'

mn,mx=Vector3(0,0,0),Vector3(0.05,0.05,0.1)
O.materials.append(JCFpmMat(type=1,density=2640,young=young,poisson=poisson,tensileStrength=20e6,cohesion=300e6,frictionAngle=radians(25),label='sphere'))
O.materials.append(JCFpmMat(type=1,frictionAngle=0,density=0,label='wall'))

walls=aabbWalls([mn,mx],thickness=0,material='wall')
wallIds=O.bodies.append(walls)

sp=pack.SpherePack()
pred=pack.inAlignedBox(mn,mx)
sp=pack.randomDensePack(pred,radius=0.001,rRelFuzz=0,returnSpherePack=True,memoizeDb='/tmp/triax.sqlite')
spheres=sp.toSimulation(material='sphere')

triax=TriaxialStressController(
	maxMultiplier=1.+4e8/young, 
	finalMaxMultiplier=1.+4e7/young, 
	thickness = 0,
	stressMask = 7,
	internalCompaction=True, 
)
newton=NewtonIntegrator(damping=damp)

def recorder():
	yade.plot.addData(
	i=O.iter,
	e11=-triax.strain[0],e22=-triax.strain[1],e33=-triax.strain[2],
	s11=-triax.stress(triax.wall_right_id)[0],#0+边界id为right
	s22=-triax.stress(triax.wall_top_id)[1],#1+边界id为top
	s33=-triax.stress(triax.wall_front_id)[2],#2+边界id为front
	numberTc=interactionLaw.nbTensCracks,
	numberSc=interactionLaw.nbShearCracks,
	unb=unbalancedForce()
)
	plot.saveDataTxt(OUT)

def stop_condition():
	extremum=max(abs(s) for s in plot.data['s33'])
	s=abs(plot.data['s33'][-1])
	e=abs(plot.data['e33'][-1])
	#if abs(s) > .5*abs(extremum) or e < 0.005:
	if e < 0.001 :
		return
	if abs(s)/abs(extremum) < 0.75:
		print('Max stress and strain:',extremum,e)
		presentcohesive_count = 0
		for i in O.interactions:
        		if hasattr(i.phys, 'isCohesive'):
            			if i.phys.isCohesive == True:
                			presentcohesive_count+=1
		print('the number of cohesive bond now is:',presentcohesive_count)
		O.wait()
	
O.engines=[
	ForceResetter(),
	InsertionSortCollider([Bo1_Sphere_Aabb(aabbEnlargeFactor=1.3,label='is2aabb'),Bo1_Box_Aabb()]),
	InteractionLoop(
		[Ig2_Sphere_Sphere_ScGeom(interactionDetectionFactor=1.3,label='ss2sc'),Ig2_Box_Sphere_ScGeom()],
		[Ip2_JCFpmMat_JCFpmMat_JCFpmPhys()],
		[Law2_ScGeom_JCFpmPhys_JointedCohesiveFrictionalPM(recordCracks=True,Key=OUT+'_Crack',label='interactionLaw')]
	),
	GlobalStiffnessTimeStepper(active=1,timeStepUpdateInterval=10,timestepSafetyCoefficient=0.8),
	triax,
	TriaxialStateRecorder(iterPeriod=100,file='WallStresses'+key),
	PyRunner(iterPeriod=int(1000),initRun=True,command='recorder()',label='data',dead=0),
	PyRunner(iterPeriod=1000,command='stop_condition()',dead=0),
	VTKRecorder(iterPeriod=500,initRun=True,fileName='triax/JFFPM-',recorders=['spheres','jcfpm','cracks'],Key=OUT+'_Crack',label='vtk',dead=1),
	newton,
]

O.step()
ss2sc.interactionDetectionFactor=-1
is2aabb.aabbEnlargeFactor=-1
cohesiveCount = 0
for i in O.interactions:
	if hasattr(i.phys, 'isCohesive'):
		if i.phys.isCohesive == True:
			cohesiveCount+=1
print('the origin total number of cohesive bond is:',cohesiveCount)

triax.goal1=triax.goal2=triax.goal3=Wy
while 1:
	#global Wy
	O.run(500,1)
	unb=unbalancedForce()
	print('unbalanced force:',unb,'mean stres:',triax.meanStress)
	if unb<stabilityThreshold and abs(Wy-triax.meanStress)/abs(Wy)<0.001:
		break

cohesiveCount = 0
for i in O.interactions:
	if hasattr(i.phys, 'isCohesive'):
		if i.phys.isCohesive == True:
			cohesiveCount+=1
print('the first total number of cohesive bond is:',cohesiveCount)

triax.internalCompaction=False
triax.stressMask=3
triax.goal1=Wy
triax.goal2=Wy
triax.goal3=rate


plot.plots={'e33':('s33',None,'unb'),'i':('numberTc','numberSc',None,'s33')}
plot.plot()
O.run()
######################

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