yade-users team mailing list archive

[xuq <question682224@xxxxxxxxxxxxxxxxxxxxx>]

New question #682224 on Yade:
https://answers.launchpad.net/yade/+question/682224

Hi,
I lern to use triaxialstresscontroller to compact particles.
But I can't stop the sumulation enen if I give the conditions,
and when I set the confining stress goal 100kpa ,
the data get from TriaxialStateRecorder is still reach 10009kpa first.
But I dont't know why,
and I don't know the error in my code either...
Please help me to check the code.

This is my code:
from yade import pack

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

# The following 5 lines will be used later for batch execution
nRead=readParamsFromTable(
	num_spheres=2000,# 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
key=table.key
targetPorosity = 0.43 #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 = 30 # contact friction during the deviatoric loading
rate=-0.02 # loading rate (strain rate)
damp=0.2 # damping coefficient
stabilityThreshold=0.001 # we test unbalancedForce against this value in different loops (see below)
young=5e6 # contact stiffness
mn,mx=Vector3(0,0,0),Vector3(1,1,1) # corners of the initial packing


## create materials for spheres and plates
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'))

## create walls around the packing
walls=aabbWalls([mn,mx],thickness=0,material='walls')
wallIds=O.bodies.append(walls)

## use a SpherePack object to generate a random loose particles packing
sp=pack.SpherePack()
sp.makeCloud(mn,mx,-1,0.3,num_spheres,False, 0.95,seed=1) #"seed" make the "random" generation always the same
O.bodies.append([sphere(center,rad,material='spheres') for center,rad in sp])
#sp.toSimulation(material='spheres')

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

triax=TriaxialStressController(
	maxMultiplier=1.0, # spheres growing factor (fast growth)
	finalMaxMultiplier=1.0, # spheres growing factor (slow growth)
	thickness = 0,
	stressMask = 7,
	internalCompaction=False, # 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()]
	),
	GlobalStiffnessTimeStepper(active=1,timeStepUpdateInterval=100,timestepSafetyCoefficient=0.8),
	triax,
	TriaxialStateRecorder(iterPeriod=100,file='WallStresses'),
	newton
]

#Display spheres with 2 colors for seeing rotations better
Gl1_Sphere.stripes=0
if nRead==0: yade.qt.Controller(), yade.qt.View()

#######################################
###   APPLYING CONFINING PRESSURE   ###
#######################################

#the value of (isotropic) confining stress defines the target stress to be applied in all three directions
triax.goal1=triax.goal2=triax.goal3=-100

if unbalancedForce()<stabilityThreshold and abs(-100-triax.stress(triax.wall_right_id)[0])/100<0.001 and abs(-100-    triax.stress(triax.wall_right_id)[1])/100<0.001 and abs(-100-triax.stress(triax.wall_right_id)[2])/100<0.001: 
    O.save('isotropicState.xml')
    print "###      Isotropic state saved      ###"
    print porosity()
    O.pause()

from yade import plot

### a function saving variables
def history():
	plot.addData(iter=O.iter,iter_=O.iter,
		        t=O.time,
                        e11=-triax.strain[0], e22=-triax.strain[1], e33=-triax.strain[2],
			ev=-triax.strain[0]-triax.strain[1]-triax.strain[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],
                        poros=porosity())
        plot.saveDataTxt('results',vars=('t','e11','e22','e33','s11','s22','s33','poros'))

if 1:
  O.engines=O.engines[0:5]+[PyRunner(iterPeriod=100,command='history()',label='recorder')]+O.engines[5:7]
else:
  O.engines[4]=PyRunner(iterPeriod=20,command='history()',label='recorder')


-- 
You received this question notification because your team yade-users is
an answer contact for Yade.