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[Amiya Prakash Das <question482040@xxxxxxxxxxxxxxxxxxxxx>]

New question #482040 on Yade:
https://answers.launchpad.net/yade/+question/482040

Hi

I am trying to understand basic behaviour of unsaturated soils. For my simulations i am using triaxial stress controller. But for my analysis i am first generating a packing with zero suction at a desired porosity and then i am using the saved packing and introducing a suction value for my further studies. I just want to know whether my approach is right or not.

Here are my scripts:

########################
#script 1 
########################

# generate loose packing
from yade import pack, qt, plot

#some parameters:
young_modulus=5e6
friction	= 0.6
angle	= atan(friction)
targetPorosity=0.42
local_damping = 0.01
stabilityThreshold=0.01
viscous_normal	= 0.021
viscous_shear	= 0.8*viscous_normal
mn	= Vector3(0,0,0)
mx	= Vector3(.05,.05,.05)
#key ='_triax_base_',

#creating a material (FrictMat):
O.materials.append(FrictMat(young=young_modulus,poisson=0.5,frictionAngle=angle,density=2600,label='spheres'))

#SphereMat=O.materials[id_SphereMat]
O.materials.append(FrictMat(young=young_modulus,poisson=0.5,frictionAngle=0,density=0,label='walls'))

#generate boundary:
walls=aabbWalls([mn,mx],thickness=0,material='walls')
wallIds=O.bodies.append(walls)

#generate particles:
sp=pack.SpherePack()

sp.makeCloud(mn,mx,rMean=.0012, seed=1)
O.bodies.append([sphere(c,r,material='spheres') for c,r in sp])

triax=TriaxialStressController(thickness = 0,
          stressMask = 7,
          internalCompaction=False, # If true the confining pressure is generated by growing particles
                 #goal1=-100,
                               #goal2=-100,
                               #goal3=-100,
                               max_vel=0.001,

)

#define engines:

O.engines=[
  ForceResetter(),
  InsertionSortCollider([Bo1_Sphere_Aabb(),Bo1_Box_Aabb()]),
  InteractionLoop(
   [Ig2_Sphere_Sphere_ScGeom(),Ig2_Box_Sphere_ScGeom()],
   [Ip2_FrictMat_FrictMat_CapillaryPhys()],	#for linear model only
   [Law2_ScGeom_FrictPhys_CundallStrack(neverErase=True)]	#for linear model only
  ),
  Law2_ScGeom_CapillaryPhys_Capillarity(capillaryPressure=0),#for linear model only
  GlobalStiffnessTimeStepper(active=1,timeStepUpdateInterval=100,timestepSafetyCoefficient=0.8),
                triax,
                TriaxialStateRecorder(iterPeriod=100,file='Target_porosity.txt'),
  NewtonIntegrator(damping=local_damping),
                #PyRunner(command='addPlotData()',iterPeriod=100)
]

#apply isotropic compression
triax.goal1=triax.goal2=triax.goal3=-10

while 1:
  O.run(1000, True)
  ##the global unbalanced force on dynamic bodies, thus excluding boundaries, which are not at equilibrium
  unb=unbalancedForce()
  print 'unbalanced force:',unb,' mean stress: ',triax.meanStress
  if unb<stabilityThreshold and abs(-10-triax.meanStress)/10<0.01:
    break

print 'out'

import sys #this is only for the flush() below
while triax.porosity>targetPorosity:
 ## we decrease friction value and apply it to all the bodies and contacts
 friction = 0.95*friction
 setContactFriction(friction)
 print "\r Friction: ",friction," porosity:",triax.porosity,
 sys.stdout.flush()
 ## while we run steps, triax will tend to grow particles as the packing
 ## keeps shrinking as a consequence of decreasing friction. Consequently
 ## porosity will decrease
 O.run(500,1)

setContactFriction(0.5)

print '\r Friction_angle:', friction

O.save('compactedState_packing.yade.gz')
O.pause()

##################
#Script 2
##################
from yade import plot
import numpy

O.load('compactedState_packing.yade.gz')

triax_iso=TriaxialStressController(thickness = 0,
          stressMask = 7,
          internalCompaction=False, # If true the confining pressure is generated by growing particles
                 max_vel=0.00001,

)

#define engines:

O.engines=[
  ForceResetter(),
  InsertionSortCollider([Bo1_Sphere_Aabb(),Bo1_Box_Aabb()]),
  InteractionLoop(
   [Ig2_Sphere_Sphere_ScGeom(),Ig2_Box_Sphere_ScGeom()],
   [Ip2_FrictMat_FrictMat_CapillaryPhys()],	#for linear model only
   [Law2_ScGeom_FrictPhys_CundallStrack(neverErase=True)]	#for linear model only
  ),
  Law2_ScGeom_CapillaryPhys_Capillarity(capillaryPressure=10),#for linear model only
  GlobalStiffnessTimeStepper(active=1,timeStepUpdateInterval=100,timestepSafetyCoefficient=0.8),
                triax_iso,
                TriaxialStateRecorder(iterPeriod=100,file='Isotropic_10_200.txt'),
  NewtonIntegrator(damping=0.01),
                PyRunner(command='addPlotData()',iterPeriod=400)
]

#apply isotropic compression
triax_iso.goal1=triax_iso.goal2=triax_iso.goal3=-200

def addPlotData():
   plot.addData(
      i=O.iter,
      s11=-triax_iso.stress(triax_iso.wall_right_id)[0],s22=-triax_iso.stress(triax_iso.wall_top_id)[1],s33=-triax_iso.stress(triax_iso.wall_front_id)[2],
      e11=-triax_iso.strain[0],e22=-triax_iso.strain[1],e33=-triax_iso.strain[2], poro=utils.porosity(), stress=-triax_iso.meanStress,
               )

#set time step and run simulation:
O.dt=0.5*PWaveTimeStep()

plot.plots={'i ':('s11','s22','s33'),' i':('e11','e22','e33'), 'stress':('poro')}

#show the plot
plot.plot()

#save the plot
#plot.saveDataTxt('Porosity_1.txt',vars=('i','s11','s22','s33','e11','e22','e33','poro','stress'))

from yade import qt
qt.View()
print('Press PLAY button')

Thanks
Amiya

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