New question #685990 on Yade:
https://answers.launchpad.net/yade/+question/685990
Hello,
I am a beginner to YADE (about 1 week old). I am trying to learn using
tutorials and the various queries on launchpad.net
My focus is on simulating consolidated drained and undrained triaxial tests
under various effective confining pressures (80kPa, 100kPa, 150 kPa and 300kPa).
As a first step, I am trying to simulate round glass beads with porosity of
1.127 and 0.613 respectively. Most of the queries online are dealing with walls
during isotropic consolidation, however I would like to have periodic boundary
conditions. I have the following code as obtained from this forum and modified
it accordingly through the help of tutorials:
Below is the code:
----------------------------------------------------------------------------------------------------------------------------------------
from __future__ import print_function
#import matplotlib#matplotlib.use('Agg')
# generate loose packing
nRead=readParamsFromTable(
num_spheres=2000,# number of spheres
compFricDegree = 44, # contact friction during the confining phase
key='_triax_CD0.61_', # put you simulation's name here
unknownOk=True
)
from yade import pack, qt, plot
from yade.params import table
sigmaIso=-1e5
O.periodic=True
num_spheres=table.num_spheres
key=table.key
targetPorosity = 0.4 #the porosity we want for the packing
compFricDegree = table.compFricDegree # initial contact friction during the
confining phase (will be decreased during the REFD compaction process)
finalFricDegree = 44 # contact friction during the deviatoric loading
rate=-0.02 # loading rate (strain rate)
damp=0.2 # damping coefficient
stabilityThreshold=0.01 # we test unbalancedForce against this value in
different loops (see below)
young=50e6 # contact stiffness
psdSizes,psdCumm=[0.25,.5,.75],[0.,0.5,1.]
sp=pack.SpherePack()
sp.makeCloud((0,0,0),(10,10,10),psdSizes=psdSizes,psdCumm=psdCumm,distributeMass=True,periodic=True)
sp.toSimulation()
print('Number of particles =',len(O.bodies))
O.engines=[
ForceResetter(),
InsertionSortCollider([Bo1_Sphere_Aabb()]),
InteractionLoop(
[Ig2_Sphere_Sphere_ScGeom()],
[Ip2_FrictMat_FrictMat_FrictPhys()],
[Law2_ScGeom_FrictPhys_CundallStrack()]
),
PeriTriaxController(label='triax',
goal=(sigmaIso,sigmaIso,sigmaIso),stressMask=7,
dynCell=True,maxStrainRate=(.001,.001,.001),
maxUnbalanced=.1,relStressTol=1e-3,
doneHook='compactionFinished()'
),
NewtonIntegrator(damping=damp),
PyRunner(command='addPlotData()',iterPeriod=100),
]
O.dt=.5*PWaveTimeStep()
def addPlotData():
plot.addData(unbalanced=unbalancedForce(),i=O.iter,
sxx=triax.stress[0],syy=triax.stress[1],szz=triax.stress[2],
exx=triax.strain[0],eyy=triax.strain[1],ezz=triax.strain[2],# save all
available energy data
ev=triax.strain[0]+triax.strain[1]+triax.strain[2],
qq=triax.stress[2]-0.5*(triax.stress[0]+triax.stress[1]),
Etot=O.energy.total(),**O.energy
)
#plot.plots={'i':('sxx','syy','szz'),}
#plot.plots={'i':('exx','eyy','ezz'),}
plot.plots={'ezz':'qq',}
plot.plot()
setContactFriction(radians(finalFricDegree))
def compactionFinished():
print('Isotropic state achieved')
print(triax.stress[0],triax.stress[1],triax.stress[2])
O.cell.trsf=Matrix3.Identity
triax.goal=(sigmaIso,sigmaIso,-.1)
triax.stressMask=7
triax.maxStrainRate=(0.5,0.5,.0001)
triax.doneHook='triaxFinished()'
triax.maxUnbalanced=10
def triaxFinished():
print('Finished')
O.pause()
---------------------------------------------------------------------------------------------------------
Some parts have not at all been used but has been simply copy-pasted into the
code.
My question is: how can I control the initial porosity using periodic triaxial
controller? I tried but it showed error: AttributeError: 'PeriTriaxController'
has no attribute 'porosity'.
Also, as I understand, the code above is only for Consolidated drained (CD)
case. I would like to simulate undrained cases (CU) for both low and high
porosities. Can someone point me in the right direction as to what changes need
to be incorporated into the code so that I can control the porosity, as well as
drained/undrained condition?
Thank you in advance,
Debdeep.
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