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[Abhineet Agarwal <question241137@xxxxxxxxxxxxxxxxxxxxx>]

Question #241137 on Yade changed:
https://answers.launchpad.net/yade/+question/241137

    Status: Answered => Open

Abhineet Agarwal is still having a problem:
# -*- coding: utf-8 -*-
#*************************************************************************
#  Copyright (C) 2010 by Bruno Chareyre                                  *
#  bruno.chareyre_at_grenoble-inp.fr                                     *
#                                                                        *
#  This program is free software; it is licensed under the terms of the  *
#  GNU General Public License v2 or later. See file LICENSE for details. *
#*************************************************************************/

## This script details the simulation of a triaxial test on sphere packings using Yade
## See the associated pdf file for detailed exercises
## the algorithms presented here have been used in published papers, namely:
## * Chareyre et al. 2002 (http://www.geosyntheticssociety.org/Resources/Archive/GI/src/V9I2/GI-V9-N2-Paper1.pdf)
## * Chareyre and Villard 2005 (https://yade-dem.org/w/images/1/1b/Chareyre&Villard2005_licensed.pdf)
## * Scholtès et al. 2009 (http://dx.doi.org/10.1016/j.ijengsci.2008.07.002)
## * Tong et al.2012 (http://dx.doi.org/10.2516/ogst/2012032)
##
## Most of the ideas were actually developped during my PhD.
## If you want to know more on micro-macro relations evaluated by triaxial simulations
## AND if you can read some french, it is here: http://tel.archives-ouvertes.fr/docs/00/48/68/07/PDF/Thesis.pdf

from yade import pack

############################################
###   DEFINING VARIABLES AND MATERIALS   ###
############################################

# The following 5 lines will be used later for batch execution
nRead=readParamsFromTable(
	num_spheres=200,# number of spheres
	compFricDegree = 30, # contact friction during the confining phase
	key='_triax_base_', # put you simulation's name here
	unknownOk=True
)
from yade.params import table

num_spheres=table.num_spheres# number of spheres
targetPorosity = 1.05/2.05 #the porosity we want for the packing for void ratio 1.05
compFricDegree = table.compFricDegree # initial contact friction during the confining phase (will be decreased during the REFD compaction process)
finalFricDegree = 30 # contact friction during the deviatoric loading
rate=0.035 # loading rate (strain rate)
damp=0.3 # damping coefficient
stabilityThreshold=0.01 # we test unbalancedForce against this value in different loops (see below)
young=3e9 # contact stiffness
mn,mx=Vector3(0,0,0),Vector3(.1,.1,.1) # corners of the initial packing
key = table.key

## create materials for spheres and plates
O.materials.append(FrictMat(young=young,poisson=0.3,frictionAngle=radians(compFricDegree),density=2600,label='spheres'))
O.materials.append(FrictMat(young=young,poisson=0.3,frictionAngle=0,density=0,label='walls'))
## create walls around the packing
walls=aabbWalls([mn,mx],thickness=0,material='walls')
wallIds=O.bodies.append(walls)


sp = pack.SpherePack()
sp.makeCloud(mn,mx,0.005,0.003,num_spheres,False, seed=1) #"seed" make the "random" generation always the same
O.bodies.append([sphere(center,rad,material='spheres') for center,rad in sp])

############################
###   DEFINING ENGINES   ###
############################

triax=TriaxialStressController(
	maxMultiplier=1.00066, # spheres growing factor (fast growth)
	finalMaxMultiplier=1.0000066, # spheres growing factor (slow growth)
	thickness = 0,
	stressMask = 7,
	internalCompaction=True, # If true the confining pressure is generated by growing particles
)

newton=NewtonIntegrator(damping=damp)

O.engines=[
	ForceResetter(),
	InsertionSortCollider([Bo1_Sphere_Aabb(),Bo1_Box_Aabb()]),
	InteractionLoop(
		[Ig2_Sphere_Sphere_ScGeom(),Ig2_Box_Sphere_ScGeom()],
		[Ip2_FrictMat_FrictMat_FrictPhys()],
		[Law2_ScGeom_FrictPhys_CundallStrack()]
	),
	## We will use the global stiffness of each body to determine an optimal timestep (see https://yade-dem.org/w/images/1/1b/Chareyre&Villard2005_licensed.pdf)
	GlobalStiffnessTimeStepper(active=1,timeStepUpdateInterval=100,timestepSafetyCoefficient=0.8),
	triax,
	TriaxialStateRecorder(iterPeriod=100,file='WallStresses'+table.key),
	newton
]

#Display spheres with 2 colors for seeing rotations better
Gl1_Sphere.stripes=0

triax.goal1=triax.goal2=triax.goal3=10000

while 1:
  #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(10000-triax.meanStress)/10000<0.0001:
    break
  O.run(1000, True)
sp.save("confinedState"+key)
if nRead==0: yade.qt.Controller(), yade.qt.View()
print "###      Isotropic state saved      ###"

###################################################
##############################
###   DEVIATORIC LOADING   ###
##############################

##We move to deviatoric loading, let us turn internal compaction off to keep particles sizes constant
triax.internalCompaction=False

## Change contact friction (remember that decreasing it would generate instantaneous instabilities)
setContactFriction(radians(finalFricDegree))

##set stress control on x and z, we will impose strain rate on y
triax.stressMask = 5
##now goal2 is the target strain rate
## we define the lateral stresses during the test, here the same 10kPa as for the initial confinement.
triax.goal1=10000
triax.goal3=10000

newton.damping=0.3

##Save temporary state in live memory. This state will be reloaded from the interface with the "reload" button.
O.saveTmp()

#####################################################
###    Example of how to record and plot data     ###
#####################################################

from yade import plot

## a function saving variables
def history():
  	plot.addData(e11=triax.strain[0], e22=triax.strain[1], e33=triax.strain[2],
  		    ev=triax.strain[0]+triax.strain[1]+triax.strain[2],
		    p = ((triax.strain[1] + triax.strain[0] +  triax.strain[2])/3.),
		    q = (triax.stress(triax.wall_top_id)[1]-triax.stress(triax.wall_front_id)[2]),
		    s11=triax.stress(triax.wall_right_id)[0],
		    s22=triax.stress(triax.wall_top_id)[1],
		    s33=triax.stress(triax.wall_front_id)[2],
		    ratio = ((triax.strain[1] + triax.strain[0] +  triax.strain[2])/3.)/(triax.stress(triax.wall_top_id)[1]-triax.stress(triax.wall_front_id)[2]),
		    i=O.iter,
		    z=yade.utils.avgNumInteractions(cutoff=0.0,skipFree=False,considerClumps=True))

if 1:
  # include a periodic engine calling that function in the simulation loop
  O.engines=O.engines[0:5]+[PyRunner(iterPeriod=1,command='history()',label='recorder')]+O.engines[5:7]
  #O.engines.insert(4,PyRunner(iterPeriod=20,command='history()',label='recorder'))
else:
  # With the line above, we are recording some variables twice. We could in fact replace the previous
  # TriaxialRecorder
  # by our periodic engine. Uncomment the following line:
  O.engines[4]=PyRunner(iterPeriod=1,command='history()',label='recorder')


cycle = 30
while cycle:
 triax.goal2 = -rate
 O.run(500,True)
 triax.goal2 = rate
 O.run(1000,True)
 triax.goal2 = -rate
 O.run(500,True)
 cycle = cycle - 1

yade.utils.plotDirections()

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