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[Swapnil <question658938@xxxxxxxxxxxxxxxxxxxxx>]

Question #658938 on Yade changed:
https://answers.launchpad.net/yade/+question/658938

Swapnil posted a new comment:
Thanks Jerome & Bruno :)

My current script is ( for 1D consolidation along z axis):

from yade import pack,plot
import math

num_spheres=1000# number of spheres
young=1e6
compFricDegree = 3 # initial contact friction during the confining phase
finalFricDegree = 30 # contact friction during the deviatoric loading
mn,mx=Vector3(0,0,0),Vector3(1,1,1) # corners of the initial packing

O.materials.append(FrictMat(young=young,poisson=0.5,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,-1,0.3333,num_spheres,False, 0.95,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(damping=0.2)

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"
 ),
 FlowEngine(dead=1,label="flow"),#introduced as a dead engine for the moment, see 2nd section
 GlobalStiffnessTimeStepper(active=1,timeStepUpdateInterval=100,timestepSafetyCoefficient=0.8),PyRunner(iterPeriod=100,command="addPlotData()"),
 triax,
 newton
]

#loading only along Z-direction (1D consolidation test)
triax.goal1=triax.goal2=0
triax.goal3= -10000 

# full saturation condition

#B. Activate flow engine and set boundary conditions in order to get permeability
flow.dead=0
flow.defTolerance=0.3
flow.meshUpdateInterval=200
flow.useSolver=3 #-----?????
flow.permeabilityFactor=1
flow.viscosity=10
flow.bndCondIsPressure=[0,0,0,0,0,1] 
flow.bndCondValue=[0,0,0,0,0,0]
flow.boundaryUseMaxMin=[0,0,0,0,0,0]
O.dt=0.1e-3
O.dynDt=False

O.run(1,1)
Qin = flow.getBoundaryFlux(4)
Qout = flow.getBoundaryFlux(5)
permeability=abs(Qin)/0.0001
print "Qin=",Qin," Qout=",Qout," permeability=",permeability

#C. now the oedometer test, drained at the top, impermeable at the bottom plate
flow.bndCondIsPressure=[0,0,0,0,0,1]
flow.bndCondValue=[0,0,0,0,0,0]
newton.damping=0


def addPlotData():
  Dz=-triax.strain[2]
  t= O.time
  plot.addData(Tx=math.sqrt(t), Dz=Dz)
  
plot.plots= {'Tx':('Dz')}
plot.plot()

I have the following questions now:
1) StressMask : I am still trying to get acquainted with the concept applied there. But I found this useful note in one of the scripts:
### switch stress/strain control using a bitmask. What is a bitmask, huh?!
	## Say x=1 if stess is controlled on x, else x=0. Same for for y and z, which are 1 or 0.
	## Then an integer uniquely defining the combination of all these tests is: mask = x*1 + y*2 + z*4
	## to put it differently, the mask is the integer whose binary representation is xyz, i.e.
## "100" (1) means "x", "110" (3) means "x and y", "111" (7) means "x and y and z", etc.

This helped me get a better idea ;)


2) 

a) For a 1D (z axis flow) we would need: triax.goal1=triax.goal2=0
triax.goal3= -10000 .

   Is it correct?

b) For flow drained at the top and bottom undrained it should be:  
     
      flow.bndCondIsPressure=[0,0,0,0,0,1]
      flow.bndCondValue=[0,0,0,0,0,0]         
       I think this is how the bit stream works here?

3) Plot:
     Is the addPlot data section to measure the change in thickness fine? I am not sure where I am going wrong. All       I see is the Dz value constantly 0 with time.

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