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[Leonard <question692392@xxxxxxxxxxxxxxxxxxxxx>]

New question #692392 on Yade:
https://answers.launchpad.net/yade/+question/692392

Hi, 
I am working on the sample preparation for triaxial compression test, there are two steps: (1st) making sample and save it, (2nd) load the sample. However, when I load the sample in step2, I found that all the penetractionDepth (i.geom.penetrationDepth) become nan, while they should have a small value in fact. Here is the MWE (modified from Bruno's  script) which can produce the problem.

### Script1(sample generation)
from __future__ import division
from yade import pack, plot
num_spheres=7000#
targetPorosity = 0.45
compFricDegree = 30
finalFricDegree = 18
rate=-0.01
damp=0.6
stabilityThreshold=0.001
young=2e8
confinement=100e3

mn,mx=Vector3(0,0,0),Vector3(0.07,0.14,0.07)

MatWall=O.materials.append(FrictMat(young=young,poisson=0.5,frictionAngle=0,density=0,label='walls'))
MatSand = O.materials.append(FrictMat(young=young,poisson=0.5,frictionAngle=radians(compFricDegree),density=2600,label='spheres'))
walls=aabbWalls([mn,mx],thickness=0,material='walls')
wallIds=O.bodies.append(walls)

sp=pack.SpherePack()
sp.makeCloud(mn,mx,-1,0.3,num_spheres,False, 0.95,seed=1)

O.bodies.append([sphere(center,rad,material='spheres') for center,rad in sp])
triax=TriaxialStressController(
    maxMultiplier=1.+3e7/young,
    finalMaxMultiplier=1.+16e4/young,
    thickness = 0,
    stressMask = 7,
    internalCompaction=True,
)
newton=NewtonIntegrator(damping=damp)

O.engines=[
    ForceResetter(),
    InsertionSortCollider([Bo1_Sphere_Aabb(),Bo1_Box_Aabb()]),
    InteractionLoop(
        [Ig2_Sphere_Sphere_ScGeom6D(),Ig2_Box_Sphere_ScGeom()],
        [Ip2_FrictMat_FrictMat_FrictPhys()],
        [Law2_ScGeom_FrictPhys_CundallStrack()]
    ),
    GlobalStiffnessTimeStepper(active=1,timeStepUpdateInterval=100,timestepSafetyCoefficient=0.8),
    triax,
    TriaxialStateRecorder(iterPeriod=100,file='WallStresses'),
    newton,
]

Gl1_Sphere.stripes=0
triax.goal1=triax.goal2=triax.goal3=-confinement

while 1:
  O.run(1000, True)
  #the global unbalanced force on dynamic bodies, thus excluding boundaries, which are not at equilibrium
  unb=unbalancedForce()
  print 'unbF:',unb,' meanStress: ',-triax.meanStress,'top:',-triax.stress(triax.wall_top_id)[1]
  if unb<stabilityThreshold and abs(-confinement-triax.meanStress)/confinement<0.0001:
      break

print "###      Isotropic state saved      ###"

import sys
while triax.porosity>targetPorosity:
	compFricDegree = 0.95*compFricDegree
	setContactFriction(radians(compFricDegree))
	print "\r Friction: ",compFricDegree," porosity:",triax.porosity,
	sys.stdout.flush()
	O.run(500,1)

O.save('sample.yade.gz')
print "###    Compacted state saved      ###"

for i in O.interactions:
	print i.geom.penetrationDepth

#### Script2(loading sample and checking penetrationDepth)
O.load('sample.yade.gz')
for i in O.interactions:
	print i.geom.penetrationDepth


Do you have any ideas for this problem?
Thanks

Leonard

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