Question #686343 on Yade changed:
https://answers.launchpad.net/yade/+question/686343
Description changed to:
Hello All,
I have a problem when I am using triaxial compaction on clumps particles. The
initial mean stress is not zero, it means when I run the code, at the first
steps in which porosity is near 1, the mean stress is not zero. For example in
my code [1], the initial mean stress is near 1 kPa. This can cause problems
when I increase the number of particles. For example, when I used 1
particles, the initial mean stress is more that 2 MPa, whereas my target
confining pressure is 100 kPa. Do you have any experiences like this?
Thank you very much.
Best Regards,
Alireza
[1]
#code#
O.reset()
from yade import utils, plot
from yade import pack, qt
from datetime import datetime
#==COKE AGGREGATE CLUMP
TEMPLATES
radz1=[0.355155e-3,0.505113e-3,0.397713e-3,0.465286e-3,0.484395e-3,0.394534e-3,0.493151e-3,0.487328e-3,0.613619e-3,0.413455e-3]
poz1=
[[1.13418e-3,-0.703895e-3,-1.20338e-3],[-0.390408e-3,0.476061e-3,-0.150612e-3],[-0.556545e-3,0.451341e-3,1.1495e-3],[-0.633942e-3,0.498253e-3,0.348231e-3],[0.0256934e-3,0.388855e-3,-0.733445e-3],[-0.218563e-3,0.504478e-3,1.54117e-3],[-0.319601e-3,0.104778e-3,0.742895e-3],[0.650678e-3,-0.76675e-3,-0.289908e-3],[0.0113115e-3,-0.207684e-3,0.00255944e-3],[0.594902e-3,-0.301473e-3,-0.878654e-3]]
template1= []
template1.append(clumpTemplate(relRadii=radz1,relPositions=poz1))
radz2=[0.330164e-3,0.504115e-3,0.399587e-3,0.614205e-3,0.466444e-3,0.495302e-3,0.394324e-3,0.486898e-3,0.444037e-3,0.489396e-3]
poz2=
[[1.16386e-3,-0.70706e-3,-1.25222e-3],[-0.39596e-3,0.482385e-3,-0.144097e-3],[-0.554928e-3,0.448475e-3,1.14685e-3],[-0.00361766e-3,-0.198211e-3,
0.00106559e-3],[-0.633362e-3,0.490424e-3,0.357391e-3],[0.0434148e-3,0.367924e-3,-0.736319e-3],[-0.218749e-3,0.504703e-3,1.54165e-3],[-0.311777e-3,
0.101954e-3,0.750235e-3],[0.621565e-3,-0.779387e-3,-0.179029e-3],[0.74e-3,-0.503202e-3,-0.795602e-3]]
template2= []
template2.append(clumpTemplate(relRadii=radz2,relPositions=poz2))
#= define the materials ===
O.materials.append(CohFrictMat(normalCohesion= 1e20, shearCohesion= 1e20,
isCohesive= True, young=1.95e7,
density=1532.2, poisson=0.3, frictionAngle= 0.0, fragile=False,
label='aggregate-814'))
O.materials.append(CohFrictMat(normalCohesion= 1e20, shearCohesion= 1e20,
isCohesive= False, young=4e9,
density=1523.6, poisson=0.3, frictionAngle= 0.0, fragile=False, label='wall'))
#= creating walls ==
walls=aabbWalls([(-15e-3,-15e-3,-15e-3),(15e-3,15e-3,15e-3)],thickness=0.0003,oversizeFactor=1.0,material='wall')
wallIds=O.bodies.append(walls)
### DEFINING ENGINES ###
O.engines=[
ForceResetter(),
InsertionSortCollider([Bo1_Sphere_Aabb(),Bo1_Box_Aabb(),Bo1_Facet_Aabb()]),
InteractionLoop([Ig2_Sphere_Sphere_ScGeom6D(),Ig2_Box_Sphere_ScGeom6D(),Ig2_Facet_Sphere_ScGeom6D()],
[Ip2_CohFrictMat_CohFrictMat_CohFrictPhys()],
[Law2_ScGeom_FrictPhys_CundallStrack(),Law2_ScGeom6D_CohFrictPhys_CohesionMoment()]
),
NewtonIntegrator(damping=0.4,gravity=[0,0,-10])
,PyRunner(command='calm()',iterPeriod=10,label='calmEngine')
]
#=Generating the aggregates==
coke=((4.303694e-04,500),(3.971601e-04,500))
nums=['t','t']
temps=[template1,template2]
mats=['aggregate-814','aggregate-814']
for i in range(len(nums)):
nums[i]=pack.SpherePack()
nums[i].makeCloud((-0.0145,-0.0145,-0.0145),(0.0145,0.0145,0.0145),rMean=coke[i][0],rRelFuzz=0.0,num=coke[i][1])
O.bodies.append([utils.sphere(c,r,material=mats[i]) for c,r in nums[i]])
O.bodies.replaceByClumps(temps[i],[1.0],discretization=5)
#===
#=== Compaction
#===
triax=TriaxialStressController(
maxMultiplier=1.000,
finalMaxMultiplier=1.000,
thickness = 0,
stressMask = 7,
internalCompaction=False,
)
O.engines=O.engines+[triax]
triax.goal1=-1.0e5
triax.goal2=-1.0e5
triax.goal3=-1.0e5
triax.wall_back_activated=True
O.dt=2e-6
while 1:
O.run(100, True)
unb=unbalancedForce()
meanS=(triax.stress(triax.wall_right_id)[0]+triax.stress(triax.wall_top_id)[1]+triax.stress(triax.wall_front_id)[2])/3
print 'mean Stress:',triax.meanStress,'porosity:', triax.porosity,'meanS:',unb
if triax.porosity<0.4 and abs(-1e5-triax.meanStress)/abs(-1e5)<0.01:
print 'Isotropic strain1:',-triax.strain[0], 'Isotropic strain
2:',-triax.strain[1], 'Isotropic strain 3:',-triax.strain[2]
break
print "### Isotropic state saved ###"
triax.depth0=triax.depth
triax.height0=tri
