| 2017-02-12 02:58:34 |
Seti |
description |
Hello all,
can I turn on setCohesionNow, setCohesionOnNewContacts in triaxial test as well? if yes, why I set these parameters the porosity & friction does not change and I face with below error? while without these consideration code works.
"Friction: 33.25 porosity: 1.0python: malloc.c:3720: _int_malloc: Assertion `(unsigned long) (size) >= (unsigned long) (nb)' failed.
Aborted (core dumped)"
the triaxial script is not different from the original one, I just copy it here if you need to know about the inputs.
Thanks,
Seti
from yade import pack,plot
############################################
### DEFINING VARIABLES AND MATERIALS ###
############################################
# The following 5 lines will be used later for batch execution
nRead=readParamsFromTable(
num_spheres=1000,# number of spheres
compFricDegree =35, # 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 = 0.42 #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 = 35# contact friction during the deviatoric loading
rate=-0.005 # loading rate (strain rate)
damp=0.3 # damping coefficient
stabilityThreshold=0.01 # we test unbalancedForce against this value in different loops (see below)
young=100e6# contact stiffness
mn,mx=Vector3(0,0,0),Vector3(0.09,0.18,0.09) # corners of the initial packing
## create materials for spheres and plates
O.materials.append(CohFrictMat(alphaKr=0.5,young=young,poisson=0.09,frictionAngle=radians(33.5),normalCohesion=7.5e3,shearCohesion=2.25e3,momentRotationLaw=True,etaRoll=0.001,density=2600,isCohesive=True,label='spheres'))
O.materials.append(CohFrictMat(young=young,poisson=0,frictionAngle=radians(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()
clumps=False #turn this true for the same example with clumps
if clumps:
## approximate mean rad of the futur dense packing for latter use
volume = (mx[0]-mn[0])*(mx[1]-mn[1])*(mx[2]-mn[2])
mean_rad = pow(0.09*volume/num_spheres,0.3333)
## define a unique clump type (we could have many, see clumpCloud documentation)
c1=pack.SpherePack([((-0.2*mean_rad,0,0),0.5*mean_rad),((0.2*mean_rad,0,0),0.5*mean_rad)])
## generate positions and input them in the simulation
sp.makeClumpCloud(mn,mx,[c1],periodic=False)
sp.toSimulation(material='spheres')
O.bodies.updateClumpProperties()#get more accurate clump masses/volumes/inertia
else:
sp.makeCloud(mn,mx,-1,0,num_spheres,False, 0.95,seed=1) #"seed" make the "random" generation always the same
#sp.makeCloud(mn,mx,0.066,num_spheres) #"seed" make the "random" generation always the same
O.bodies.append([sphere(center,rad,material='spheres') for center,rad in sp])
#or alternatively (higher level function doing exactly the same):
#sp.toSimulation(material='spheres')
############################
### DEFINING ENGINES ###
############################
triax=TriaxialStressController(
## TriaxialStressController will be used to control stress and strain. It controls particles size and plates positions.
## this control of boundary conditions was used for instance in http://dx.doi.org/10.1016/j.ijengsci.2008.07.002
maxMultiplier=1.+2e4/young, # spheres growing factor (fast growth)
finalMaxMultiplier=1.+2e3/young, # spheres growing factor (slow growth)
thickness = 0,
## 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.
stressMask = 7,
internalCompaction=True, # If true the confining pressure is generated by growing particles
)
newton=NewtonIntegrator(damping=damp)
########################################
#Modified engine
##################################
O.engines=[
ForceResetter(),
InsertionSortCollider([Bo1_Sphere_Aabb(),Bo1_Box_Aabb()]),
InteractionLoop(
[Ig2_Sphere_Sphere_ScGeom(),Ig2_Box_Sphere_ScGeom()],
[Ip2_FrictMat_FrictMat_FrictPhys (),Ip2_CohFrictMat_CohFrictMat_CohFrictPhys(setCohesionNow = True, setCohesionOnNewContacts = True,label="cohesiveIp")],
[Law2_ScGeom_FrictPhys_CundallStrack(),Law2_ScGeom_CohFrictPhys_CohesionMoment(
useIncrementalForm=True, #useIncrementalForm is turned on as we want plasticity on the contact moments
always_use_moment_law=False, #if we want "rolling" friction even if the contact is not cohesive (or cohesion is broken), we will have to turn this true somewhere
label='cohesiveLaw')]
),
## 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='150,damp0.8,rate 0.005,NEW50,alphaKr=0.5,young=100e6,poisson=0.09,frictionAngle=radians(50),normalCohesion=7.5e10,shearCohesion=2.25e10,etaRoll=0.025,density=2600,wall35,'+key),
newton
]
##########################################################
#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
if nRead==0: yade.qt.Controller(), yade.qt.View()
## UNCOMMENT THE FOLLOWING SECTIONS ONE BY ONE
## DEPENDING ON YOUR EDITOR, IT COULD BE DONE
## BY SELECTING THE CODE BLOCKS BETWEEN THE SUBTITLES
## AND PRESSING CTRL+SHIFT+D
#if nRead==0: yade.qt.Controller(), yade.qt.View()
print 'Number of elements: ', len(O.bodies)
print 'Box Volume: ', triax.boxVolume
#######################################
### 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=-150000
#while 1:
#O.run(1000, True)
##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<0.001:
#break
#O.save('confinedState'+key+'.yade.gz')
#print "### Isotropic state saved ###"
###################################################
### REACHING A SPECIFIED POROSITY PRECISELY ###
###################################################
### We will reach a prescribed value of porosity with the REFD algorithm
### (see http://dx.doi.org/10.2516/ogst/2012032 and
### http://www.geosyntheticssociety.org/Resources/Archive/GI/src/V9I2/GI-V9-N2-Paper1.pdf)
import sys #this is only for the flush() below
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()
## while we run steps, triax will tend to grow particles as the packing
## keeps shrinking as a consequence of decreasing friction. Consequently
## porosity will decrease
O.run(500,1)
O.save('compactedStateBEL20,young=63.9e8'+key+'.yade.gz')
print "### Compacted 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
triax.goal2=rate
## we define the lateral stresses during the test, here the same 10kPa as for the initial confinement.
triax.goal1=-150000
triax.goal3=-150000
##we can change damping here. What is the effect in your opinion?
newton.damping=0.1 |
Hello all,
can I turn on setCohesionNow, setCohesionOnNewContacts in triaxial test as well? if yes, why I set these parameters the porosity & friction does not change and I face with below error? while without these consideration code works.
"Friction: 33.25 porosity: 1.0python: malloc.c:3720: _int_malloc: Assertion `(unsigned long) (size) >= (unsigned long) (nb)' failed.
Aborted (core dumped)"
the triaxial script is not different from the original one, I just copy it here if you need to know about the inputs.
Thanks,
Seti
from yade import pack,plot
############################################
### DEFINING VARIABLES AND MATERIALS ###
############################################
# The following 5 lines will be used later for batch execution
nRead=readParamsFromTable(
num_spheres=1000,# number of spheres
compFricDegree =35, # 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 = 0.42 #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 = 35# contact friction during the deviatoric loading
rate=-0.005 # loading rate (strain rate)
damp=0.3 # damping coefficient
stabilityThreshold=0.01 # we test unbalancedForce against this value in different loops (see below)
young=100e6# contact stiffness
mn,mx=Vector3(0,0,0),Vector3(0.09,0.18,0.09) # corners of the initial packing
## create materials for spheres and plates
O.materials.append(CohFrictMat(alphaKr=0.5,young=young,poisson=0.09,frictionAngle=radians(33.5),normalCohesion=7.5e3,shearCohesion=2.25e3,momentRotationLaw=True,etaRoll=0.001,density=2600,isCohesive=True,label='spheres'))
O.materials.append(CohFrictMat(young=young,poisson=0,frictionAngle=radians(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()
clumps=False #turn this true for the same example with clumps
if clumps:
## approximate mean rad of the futur dense packing for latter use
volume = (mx[0]-mn[0])*(mx[1]-mn[1])*(mx[2]-mn[2])
mean_rad = pow(0.09*volume/num_spheres,0.3333)
## define a unique clump type (we could have many, see clumpCloud documentation)
c1=pack.SpherePack([((-0.2*mean_rad,0,0),0.5*mean_rad),((0.2*mean_rad,0,0),0.5*mean_rad)])
## generate positions and input them in the simulation
sp.makeClumpCloud(mn,mx,[c1],periodic=False)
sp.toSimulation(material='spheres')
O.bodies.updateClumpProperties()#get more accurate clump masses/volumes/inertia
else:
sp.makeCloud(mn,mx,-1,0,num_spheres,False, 0.95,seed=1) #"seed" make the "random" generation always the same
#sp.makeCloud(mn,mx,0.066,num_spheres) #"seed" make the "random" generation always the same
O.bodies.append([sphere(center,rad,material='spheres') for center,rad in sp])
#or alternatively (higher level function doing exactly the same):
#sp.toSimulation(material='spheres')
############################
### DEFINING ENGINES ###
############################
triax=TriaxialStressController(
## TriaxialStressController will be used to control stress and strain. It controls particles size and plates positions.
## this control of boundary conditions was used for instance in http://dx.doi.org/10.1016/j.ijengsci.2008.07.002
maxMultiplier=1.+2e4/young, # spheres growing factor (fast growth)
finalMaxMultiplier=1.+2e3/young, # spheres growing factor (slow growth)
thickness = 0,
## 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.
stressMask = 7,
internalCompaction=True, # If true the confining pressure is generated by growing particles
)
newton=NewtonIntegrator(damping=damp)
########################################
#Modified engine
##################################
O.engines=[
ForceResetter(),
InsertionSortCollider([Bo1_Sphere_Aabb(),Bo1_Box_Aabb()]),
InteractionLoop(
[Ig2_Sphere_Sphere_ScGeom(),Ig2_Box_Sphere_ScGeom()],
[Ip2_FrictMat_FrictMat_FrictPhys (),Ip2_CohFrictMat_CohFrictMat_CohFrictPhys(setCohesionNow = True, setCohesionOnNewContacts = True,label="cohesiveIp")],
[Law2_ScGeom_FrictPhys_CundallStrack(),Law2_ScGeom_CohFrictPhys_CohesionMoment(
useIncrementalForm=True, #useIncrementalForm is turned on as we want plasticity on the contact moments
always_use_moment_law=False, #if we want "rolling" friction even if the contact is not cohesive (or cohesion is broken), we will have to turn this true somewhere
label='cohesiveLaw')]
),
## 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='150,damp0.8,rate 0.005,NEW50,alphaKr=0.5,young=100e6,poisson=0.09,frictionAngle=radians(50),normalCohesion=7.5e10,shearCohesion=2.25e10,etaRoll=0.025,density=2600,wall35,'+key),
newton
]
##########################################################
#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
if nRead==0: yade.qt.Controller(), yade.qt.View()
## UNCOMMENT THE FOLLOWING SECTIONS ONE BY ONE
## DEPENDING ON YOUR EDITOR, IT COULD BE DONE
## BY SELECTING THE CODE BLOCKS BETWEEN THE SUBTITLES
## AND PRESSING CTRL+SHIFT+D
#if nRead==0: yade.qt.Controller(), yade.qt.View()
print 'Number of elements: ', len(O.bodies)
print 'Box Volume: ', triax.boxVolume
#######################################
### 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=-150000
#while 1:
#O.run(1000, True)
##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<0.001:
#break
#O.save('confinedState'+key+'.yade.gz')
#print "### Isotropic state saved ###"
###################################################
### REACHING A SPECIFIED POROSITY PRECISELY ###
###################################################
### We will reach a prescribed value of porosity with the REFD algorithm
### (see http://dx.doi.org/10.2516/ogst/2012032 and
### http://www.geosyntheticssociety.org/Resources/Archive/GI/src/V9I2/GI-V9-N2-Paper1.pdf)
import sys #this is only for the flush() below
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()
## while we run steps, triax will tend to grow particles as the packing
## keeps shrinking as a consequence of decreasing friction. Consequently
## porosity will decrease
O.run(500,1)
O.save('compactedStateBEL20,young=63.9e8'+key+'.yade.gz')
print "### Compacted 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
triax.goal2=rate
## we define the lateral stresses during the test, here the same 10kPa as for the initial confinement.
triax.goal1=-150000
triax.goal3=-150000
##we can change damping here. What is the effect in your opinion?
newton.damping=0.1 |
|
