Yade

setCohesionNow=True problem

Asked by Ferenc Safranyik

Dear All,

I try to make a simply simulation of a very cohesive particulate solid. To this CohFrictMat material model was used. After unbalancedForce was decreased I try to turn on cohesion on every contact but I get an erre: "Segmentation fault (core dumped)" and I can not recognise until this time the problem. Can anybody help to me? Thanks in advance!

Some piece of the code:

densT = 2600
ET = 5e5 * 25
nuT = .9
frictAngT = .2
nCoh = 1e8
sCoh = 1e8
eRoll = .1

talaj = O.materials.append(CohFrictMat(young=ET,poisson=nuT,density=densT,frictionAngle=frictAngT,normalCohesion=nCoh,
                                     shearCohesion=sCoh,isCohesive=True,momentRotationLaw=True,etaRoll=eRoll,label='talaj'))
acel = O.materials.append(FrictMat(young=EA,poisson=nuA,density=densA,frictionAngle=frictAngA,label='acel'))

doboz = O.bodies.append(geom.utils.facetBox((1.25,0,.05),(.25,.2,.15),wallMask=63, color=(.2,.2,.0),material = 'acel'))

Sugar1 = .02
felho = pack.SpherePack()
felho.makeCloud((1,-.2,-.1),(1.5,.2,.2),rMean=Sugar1)
particles = O.bodies.append([sphere(c,r,material='talaj',color=(.3,.8,.1)) for c,r in felho])

O.engines=[
        ForceResetter(),
        InsertionSortCollider([Bo1_Sphere_Aabb(),Bo1_Box_Aabb(),Bo1_Facet_Aabb()]),
        InteractionLoop(
                [Ig2_Sphere_Sphere_ScGeom(),Ig2_Facet_Sphere_ScGeom(),Ig2_Box_Sphere_ScGeom()],
                [Ip2_FrictMat_FrictMat_FrictPhys(),Ip2_CohFrictMat_CohFrictMat_CohFrictPhys(label='coh')],
                [Law2_ScGeom_FrictPhys_CundallStrack(),Law2_ScGeom6D_CohFrictPhys_CohesionMoment(
   useIncrementalForm=True,
   always_use_moment_law = True)]
        ),
        NewtonIntegrator(damping=.4,gravity=(0,0,-9.81),label='newton'),
]

O.dt=.01*utils.PWaveTimeStep()

O.engines=O.engines + [PyRunner(command='ment()',iterPeriod = 1,label='ment')]

def ment():
 plot.addData(i=O.iter,uF=utils.unbalancedForce())
 if O.iter > 80000 and utils.unbalancedForce() < .05:
                coh.setCohesionNow=True

Question information

Language:
English Edit question
Status:
Solved
For:
Yade Edit question
Assignee:
No assignee Edit question
Solved by:
Ferenc Safranyik
Solved:
Last query:
Last reply:
Revision history for this message
Jérôme Duriez (jduriez) said : 		#1

Hi,

If I were you, I would first try to simplify your script. Do you really need that many Bo1 / Ig2 / Ip2 /Law2 functors ?

It should be possible to just use CohFrictMat for instance (and no FrictMat), possibly two of them: one with non zero cohesive properties, and an other one with zero cohesive properties, if this was what you were looking for.

Jérôme

Revision history for this message
Bruno Chareyre (bruno-chareyre) said : 		#2

File "test.py", line 11, in <module>
     acel =
O.materials.append(FrictMat(young=EA,poisson=nuA,density=densA,frictionAngle=frictAngA,label='acel'))
NameError: name 'EA' is not defined

Please check [1].

Bruno

[1] https://yade-dem.org/wiki/Howtoask

Revision history for this message
Ferenc Safranyik (safranyikf) said : 		#3

Dear Jerome and Bruno,

thanks for your reply and sorry my mistake: I forget to write in my question some material parameters...

The code was changed based on your suggestions and now it is working! Thanks!

densT = 2600
ET = 5e5 * 25
nuT = .9
frictAngT = .2
nCoh = 1e8
sCoh = 1e8
eRoll = .1

EA = 2.1e8
nuA = .3
densA = 7800
frictAngA = .35

talaj = O.materials.append(CohFrictMat(young=ET,poisson=nuT,density=densT,frictionAngle=frictAngT,normalCohesion=nCoh,
                                     shearCohesion=sCoh,isCohesive=True,momentRotationLaw=True,etaRoll=eRoll,label='talaj'))
acel = O.materials.append(CohFrictMat(young=EA,poisson=nuA,density=densA,frictionAngle=frictAngA,normalCohesion=0,
                                      shearCohesion=0,etaRoll=.1,isCohesive=False,momentRotationLaw=False,label='acel'))

doboz = O.bodies.append(geom.utils.facetBox((1.25,0,.05),(.25,.2,.15),wallMask=63, color=(.2,.2,.0),material = 'acel'))

Sugar1 = .02
felho = pack.SpherePack()
felho.makeCloud((1,-.2,-.1),(1.5,.2,.2),rMean=Sugar1)
particles = O.bodies.append([sphere(c,r,material='talaj',color=(.3,.8,.1)) for c,r in felho])

O.engines=[
        ForceResetter(),
        InsertionSortCollider([Bo1_Sphere_Aabb(),Bo1_Facet_Aabb()]),
        InteractionLoop(
                [Ig2_Sphere_Sphere_ScGeom6D(),Ig2_Facet_Sphere_ScGeom6D()],
                [Ip2_CohFrictMat_CohFrictMat_CohFrictPhys(label='coh')],
                [Law2_ScGeom6D_CohFrictPhys_CohesionMoment(
   useIncrementalForm=True,
   always_use_moment_law = True)]
        ),
        NewtonIntegrator(damping=.4,gravity=(0,0,-9.81),label='newton'),
]

O.dt=.01*utils.PWaveTimeStep()

O.engines=O.engines + [PyRunner(command='ment()',iterPeriod = 1,label='ment')]

def ment():
 plot.addData(i=O.iter,uF=utils.unbalancedForce())
 if O.iter > 80000 and utils.unbalancedForce() < .05:
                coh.setCohesionNow=True