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[Swapnil <question659526@xxxxxxxxxxxxxxxxxxxxx>]

New question #659526 on Yade:
https://answers.launchpad.net/yade/+question/659526

Hello friends,
I have been trying to simulate a triaxial test on dry granular material (say Sand). 

The aims are:
Try the dry sample with certain set of properties (will have to check how many I can test ;)) .
Apply the triaxial confining pressure by means of strain-loading (that is, load sample with a certain strain rate to induce a certain confining pressure).
Then, plot the stress-strain curve and other curves. I am currently trying the former.

The current script is as follows:

from yade import pack,plot
import math

num_spheres=10000   # number of spheres
young=3e9
compFricDegree = 30 # initial contact friction during the confining phase
finalFricDegree = 30 # contact friction during the deviatoric loading
mn,mx=Vector3(0,0,0),Vector3(0.1,0.1,0.1) # corners of the initial packing

O.materials.append(FrictMat(young=young,poisson=0.3,frictionAngle=radians(compFricDegree),density=2600,label='spheres'))
O.materials.append(FrictMat(young=young,poisson=0.5,frictionAngle=0,density=0,label='walls'))
walls=aabbWalls([mn,mx],thickness=0,material='walls')
wallIds=O.bodies.append(walls)

sp=pack.SpherePack()
sp.makeCloud(mn,mx,-1,0.5,num_spheres,False, 0.50,seed=1) #"seed" make the "random" generation always the same
sp.toSimulation(material='spheres')

triax=TriaxialStressController(
 maxMultiplier=1.+2e4/young, # spheres growing factor (fast growth)
 finalMaxMultiplier=1.+2e3/young, # spheres growing factor (slow growth)
 thickness = 0,
 stressMask = 7,
 max_vel = 0.005,
 internalCompaction=True, # If true the confining pressure is generated by growing particles
)

newton=NewtonIntegrator(gravity=(0,0,-9.81),damping=0.3)

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()],label="iloop"
 ),
 
GlobalStiffnessTimeStepper(active=1,timeStepUpdateInterval=100,timestepSafetyCoefficient=0.8),PyRunner(iterPeriod=100,command="addPlotData()"),
 triax,
 newton
]


strain_rate=-0.0005
triax.goal1=triax.goal2=triax.goal3=strain_rate 


O.dt=0.5*PWaveTimeStep()
def addPlotData():
  plot.addData(Sz=-triax.stress[0], Dz=-triax.strain[0])
  
plot.plots= {'Dz':('Sz')}
plot.plot()


My question is:
1) Is the script fine considering what I intend to perform or am I making some conceptual/coding error

2) I am unable to generate the plot for the stress-strain along one of the axis. Upon running the simulation,  I receive the following error:
'instancemethod' object has no attribute '__getitem__'
I do not know how this can be rectified. Any clues?


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