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[Leonard <question686179@xxxxxxxxxxxxxxxxxxxxx>]

Question #686179 on Yade changed:
https://answers.launchpad.net/yade/+question/686179

    Status: Answered => Open

Leonard is still having a problem:
Hi Robert,
Many thanks for your reply.
>Depends on what you want to simulate. 
What I want to simulate is the common PSD curve for a soil. For a general particle size distribution curve of soil, the Y-axis is percentage passing by mass, the x-axis is particle size (diameter) based on what I understand.
What I am confused is whether the distributeMass command controls on Y-axis or on X-axis? 
For example, if distributeMass command controls on Y-axis, it may mean that percentage passing by mass (distributeMass=True) or by count (distributeMass=False)?
If distributeMass command controls on X-axis, it may mean that X-axis is particle diameter (distributeMass=False) or particle mass (distributeMass=True)?

>spheres using a common multiplier
Thanks, it is clear.

>Maybe they used internalCompaction=False.
I'm still interested in how it is achieved by setting internalCompaction=False.
I have also tried internalCompaction=False, the problem is that when set internalCompaction=False, the size of the sample changed.
For example, the size of initial packing is 0.7*0.7*1.4 (mn,mx=Vector3(0,0,0),Vector3(0.7,0.7,1.4)), when I set internalCompaction=True, after compacted state completed, the size of the packing stays around 0.7*0.7*1.4. However, when I set internalCompaction=False, after compacted state completed, the size of the packing is changed to 0.26*0.26*0.9, and in this case, I can not obtain a reasonable sample in terms of size. The following MWE may show this question by changing internalCompaction= True to False. 
###########
from yade import pack, plot
nRead=readParamsFromTable(
	num_spheres=1000,
	compFricDegree = 30,
	key='_triax_base_',
	unknownOk=True
)
from yade.params import table

num_spheres=table.num_spheres
key=table.key
targetPorosity = 0.43
compFricDegree = table.compFricDegree
finalFricDegree = 30
rate=-0.02
damp=0.2
stabilityThreshold=0.01
young=5e6
mn,mx=Vector3(0,0,0),Vector3(0.7,0.7,1.4)

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)
O.bodies.append([sphere(center,rad,material='spheres') for center,rad in sp])

Gl1_Sphere.quality=3

###   DEFINING ENGINES   ###
triax=TriaxialStressController(
	maxMultiplier=1.+2e4/young,
	finalMaxMultiplier=1.+2e3/young,
	thickness = 0,
	stressMask = 7,
	internalCompaction=True,## please change True to False here to look at what I say
)

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,
	newton
]

Gl1_Sphere.stripes=0
if nRead==0: yade.qt.Controller(), yade.qt.View()

###   APPLYING CONFINING PRESSURE   ###
triax.goal1=triax.goal2=triax.goal3=-10000
while 1:
	O.run(1000, True)
	unb=unbalancedForce()
	print 'unbalanced force:',unb,' mean stress: ',triax.meanStress
	if unb<stabilityThreshold and abs(-10000-triax.meanStress)/10000<0.001:
		break

print "###      Isotropic state  saved      ###"
###   REACHING A SPECIFIED POROSITY PRECISELY   ###
import sys
while triax.porosity>targetPorosity:
	# we decrease friction value and apply it to all the bodies and contacts
	compFricDegree = 0.95*compFricDegree
	setContactFriction(radians(compFricDegree))
	print "\r Friction: ",compFricDegree," porosity:",triax.porosity,
	sys.stdout.flush()
	O.run(500,1)
print "###    Compacted state saved      ###"
########################
Cheers,
Leonard

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