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[Yor1 <question273367@xxxxxxxxxxxxxxxxxxxxx>]

New question #273367 on Yade:
https://answers.launchpad.net/yade/+question/273367

Hello,

I realise a triaxial compression test.
I want to increase the major stress every 5000 iterations
For example 
0<= i < 5000 : sigma1=2MPa
5000 <= i <10000 : sigma1 = 3MPa
10000 <= i <15000 : sigma1 = 4 MPa etc...

The problem is that my code increase the major stress once and the major stress becomes constant.
Best regards
Jabrane

This is my code:

from yade import ymport, utils , plot
import math

PACKING='X10Y20Z10_5k'
OUT=PACKING+'_compressionTest_5MPa_r002_frictWall'

l
DAMP=0.4 
saveData=100 
iterMax=2000000 
saveVTK=10000 


confinement=-2e6
uniaxial_stress=-3e6
delta_stress=-1e6
stress_max=-20e6


intR=1.47618
DENS=4000
YOUNG=65e9 
FRICT=10
ALPHA=0.4
TENS=8e6 
COH=160e6

def sphereMat(): return JCFpmMat(type=1,density=DENS,young=YOUNG,poisson = ALPHA,frictionAngle=radians(FRICT),tensileStrength=TENS,cohesion=COH)
def wallMat(): return JCFpmMat(type=0,density=DENS,young=YOUNG,frictionAngle=radians(0))


O.bodies.append(ymport.text(PACKING+'.spheres',scale=1.,shift=Vector3(0,0,0),material=sphereMat))

dim=utils.aabbExtrema()
xinf=dim[0][0]
xsup=dim[1][0]
X=xsup-xinf
yinf=dim[0][1]
ysup=dim[1][1]
Y=ysup-yinf
zinf=dim[0][2]
zsup=dim[1][2]
Z=zsup-zinf

R=0
Rmax=0
numSpheres=0.
for o in O.bodies:
 if isinstance(o.shape,Sphere):
   numSpheres+=1
   R+=o.shape.radius
   if o.shape.radius>Rmax:
     Rmax=o.shape.radius
Rmean=R/numSpheres

O.reset() 

mn,mx=Vector3(xinf+0.1*Rmean,yinf+0.1*Rmean,zinf+0.1*Rmean),Vector3(xsup-0.1*Rmean,ysup-0.1*Rmean,zsup-0.1*Rmean)
walls=utils.aabbWalls(oversizeFactor=1.5,extrema=(mn,mx),thickness=min(X,Y,Z)/100.,material=wallMat)
wallIds=O.bodies.append(walls)


O.bodies.append(ymport.text(PACKING+'.spheres',scale=1.,shift=Vector3(0,0,0),material=sphereMat))


for o in O.bodies:
 if isinstance(o.shape,Sphere):
   o.shape.color=(0.7,0.5,0.3)

O.engines=[
        ForceResetter(),
        InsertionSortCollider([Bo1_Box_Aabb(),Bo1_Sphere_Aabb(aabbEnlargeFactor=intR,label='Saabb')]),
	InteractionLoop(
		[Ig2_Sphere_Sphere_ScGeom(interactionDetectionFactor=intR,label='SSgeom'),Ig2_Box_Sphere_ScGeom()],
		[Ip2_JCFpmMat_JCFpmMat_JCFpmPhys(cohesiveTresholdIteration=1,label='interactionPhys')],
		[Law2_ScGeom_JCFpmPhys_JointedCohesiveFrictionalPM(recordCracks=True,Key=OUT,label='interactionLaw')]
	),
        TriaxialStressController(internalCompaction=False,label='triax',externalWork=0),
        GlobalStiffnessTimeStepper(active=1,timeStepUpdateInterval=10,timestepSafetyCoefficient=0.4, defaultDt=0.1*utils.PWaveTimeStep()),
        NewtonIntegrator(damping=DAMP,label="newton"),
        PyRunner(iterPeriod=int(saveData),initRun=True,command='recorder()',label='data'),
        VTKRecorder(iterPeriod=int(saveVTK),initRun=True,fileName=OUT+'-',recorders=['spheres','jcfpm','cracks'],Key=OUT,label='vtk')
]
 

tensCks=shearCks=cks=cks0=0
e10=e20=e30=0
def recorder():
    global tensCks, shearCks, e10,e20,e30
    tensCks=0
    shearCks=0
    for o in O.bodies:
	tensCks+=o.state.tensBreak
	shearCks+=o.state.shearBreak
    yade.plot.addData( t=O.time
			,i=O.iter
			,e1=triax.strain[0]-e10
			,e2=triax.strain[1]-e20
			,e3=triax.strain[2]-e30
			,s1=triax.stress(triax.wall_right_id)[0]
			,s2=triax.stress(triax.wall_top_id)[1]
			,s3=triax.stress(triax.wall_front_id)[2]
			,tc=0.5*tensCks,sc=0.5*shearCks,unbF=utils.unbalancedForce() 
    )
    plot.saveDataTxt(OUT)

plot.plots={'i':('s1','s2','s3')}
plot.plot()


O.step();

SSgeom.interactionDetectionFactor=-1.
Saabb.aabbEnlargeFactor=-1.

numSSlinks=0
numCohesivelinks=0
numFrictionalLinks=0
for i in O.interactions:
    if not i.isReal : continue
    if isinstance(O.bodies[i.id1].shape,Sphere) and isinstance(O.bodies[i.id2].shape,Sphere):
     numSSlinks+=1
     if i.phys.isCohesive :
      numCohesivelinks+=1
     else :
      numFrictionalLinks+=1

print "nbSpheres=", numSpheres," | coordination number =", 2.0*numCohesivelinks/numSpheres


triax.stressMask=7
triax.goal1=confinement
triax.goal2=confinement
triax.goal3=confinement
triax.max_vel=0.001

while 1:
  if confinement==0: 
    O.run(1000,True) 
    break
  O.run(100,True)
  unb=unbalancedForce()
  meanS=abs(triax.stress(triax.wall_right_id)[0]+triax.stress(triax.wall_top_id)[1]+triax.stress(triax.wall_front_id)[2])/3
  print 'unbalanced force:',unb,' mean stress: ',meanS
  if unb<0.005 and abs(meanS-abs(confinement))/abs(confinement)<0.001:
    O.run(1000,True) # to stabilize the system
    e10=triax.strain[0]
    e20=triax.strain[1]
    e30=triax.strain[2]
    break


O.bodies[wallIds[2]].mat.frictionAngle=radians(30)
O.bodies[wallIds[3]].mat.frictionAngle=radians(30)

triax.stressMask=7
triax.goal1=confinement
triax.goal3=confinement
triax.goal2=uniaxial_stress


while 1:
	O.run(5000,True)
	triax.goal2+=delta_stress
	print 'stress', triax.goal2 
	break
	
O.run(iterMax)

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