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[Jan Stránský <question245254@xxxxxxxxxxxxxxxxxxxxx>]

Question #245254 on Yade changed:
https://answers.launchpad.net/yade/+question/245254

Jan Stránský proposed the following answer:
Hi Henry,

IPyhys of your interactions are of type CohFrictPhys, as defined in
O.engines. However, CohFrictPhys does not have any of the parameters you
try to assign (normalCohesion, shearCohesion, frictionAngle), see [1]. So
nothing is changed.

The change of material parameters will have effect only for newly created
interactions.

cheers
Jan

[1] https://yade-dem.org/doc/yade.wrapper.html#yade.wrapper.CohFrictPhys



2014-03-10 16:06 GMT+01:00 Henry <question245254@xxxxxxxxxxxxxxxxxxxxx>:

> Question #245254 on Yade changed:
> https://answers.launchpad.net/yade/+question/245254
>
> Henry posted a new comment:
> Thanks to Jan.
>  Follows is a part of my script. I want to change the material paramteres
> during the simulation. But I found there is no change whether use the
> function of 'Par_Change() or not .
>
> The script:
>
>
> SoilMat=O.materials.append(CohFrictMat(young=Young_Soil,poisson=0.2,density=den,frictionAngle=Frict_0,normalCohesion=Coh_0,shearCohesion=0.1*Coh_0,isCohesive=True,momentRotationLaw=True,etaRoll=0.1,label='soil'))
>
> #def sphereMat(): return
> JCFpmMat(type=1,young=5.0e11,frictionAngle=Frict_0,density=3000) ## Rq:
> density needs to be adapted as porosity of real rock is different to
> granular assembly due to difference in porosity
> (utils.sumForces(baseBodies,(0,1,0))/(Z*X) should be equal to Gamma*g*h
> with h=Y, g=9.82 and Gamma=2700 kg/m3
>
> O.bodies.append(ymport.text(packing+'.spheres',scale=1.0,shift=Vector3(0,0,0),material=SoilMat))
>
> O.engines=[
>
>         ForceResetter(),
>
> InsertionSortCollider([Bo1_Sphere_Aabb(aabbEnlargeFactor=interactionRadius,label='is2aabb'),Bo1_Box_Aabb()]),
>         InteractionLoop(
>
> [Ig2_Sphere_Sphere_ScGeom6D(interactionDetectionFactor=interactionRadius,label='ss2d3dg'),Ig2_Box_Sphere_ScGeom6D()],#Ig2_Sphere_Sphere_ScGeom(interactionDetectionFactor=interactionRadius,label='ss2d3dg'),Ig2_Box_Sphere_ScGeom()],
>         [Ip2_FrictMat_FrictMat_FrictPhys(),
>
> Ip2_CohFrictMat_CohFrictMat_CohFrictPhys(label='cohesiveIp')],#setCohesionNow=False,setCohesionOnNewContacts=False,
>
> [Law2_ScGeom_FrictPhys_CundallStrack(),Law2_ScGeom6D_CohFrictPhys_CohesionMoment(
>                         useIncrementalForm=True, #useIncrementalForm is
> turned on as we want plasticity on the contact moments
>                         always_use_moment_law=True,  #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')]
>         ),
>
> GlobalStiffnessTimeStepper(timeStepUpdateInterval=100,timestepSafetyCoefficient=0.8,defaultDt=O.dt),
>     PyRunner(iterPeriod=1000,initRun=True,command='Par_Change()'),
>         NewtonIntegrator(damping=0.5,gravity=(0.,-9.82,0.),label='Grav'),
>
> ]
>
>
> def Par_Change():
>     global Fos_Step,Coh_0,Frict_0
>     global Fos,D_step
>     if O.iter>Fos_Step:# and utils.unbalancedForce()<0.1:
>         Fos=Fos+0.05
>         Fos_Step=D_step+O.iter
>         Fri_Fos=math.atan(math.tan(Frict_0)/Fos)
>          # here we modify the material and interaction physics
>         for b in O.bodies:
>             if b.material.id==0:
>                 b.mat.frictionAngle=Fri_Fos
>                 b.mat.normalCohesion=Coh_0/Fos
>                 b.mat.shearCohesion=0.1*Coh_0/Fos
>         for i in O.interactions:
>             if O.bodies[i.id1].material.id==1 or O.bodies[i.id2].
> material.id==1:
>                 i.phys.normalCohesion=0.0
>                 i.phys.shearCohesion=0.0
>                 i.phys.frictionAngle=0.0
>             else:
>                 i.phys.normalCohesion=Coh_0/Fos
>                 i.phys.shearCohesion=0.1*Coh_0/Fos
>                 i.phys.frictionAngle=Fri_Fos
>
> Thanks a lot!
> Henry
>
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