contact problem of applying ScGeom on polyhedra particle

Asked by lip on 2019-06-03

hello
i was applying Ig2_Polyhedra_Polyhedra_ScGeom() to simution the deposit of polyhedra particles, the boundary is formed by fixed polyhedra. But when the polyhedra particles contacted with the fixed polyhedra boundary, they just get through the boundary, i have tried many value of timestep,but it is all the same. i do not know what is wrong, i would appreciate it if you can help me.
below is my code:
from yade import polyhedra_utils,pack,plot,utils
import random

n = FrictMat(young=1e10,poisson=.05)

O.materials.append(n)

#the boundary of particle deposit
v1=((0,0,0),(0,3.2,0),(0,0,6),(0,3.2,6),(-0.1,0,0),(-0.1,3.2,0),(-0.1,0,6),(-0.1,3.2,6))
v2=((0,0,0),(0,0,6),(18,0,0),(18,0,6),(0,0.1,0),(0,0.1,6),(18,0.1,0),(18,0.1,6))
v3=((0,3.1,0),(0,3.1,6),(18,3.1,0),(18,3.1,6),(0,3.2,0),(0,3.2,6),(18,3.2,0),(18,3.2,6))
v4=((0,0,0),(0,3.2,0),(18,3.2,0),(18,0,0),(0,0,-0.1),(0,3.2,-0.1),(18,3.2,-0.1),(18,0,-0.1))
v5=((3,0.1,0),(3,3.1,0),(3,0.1,6),(3,3.1,6),(3.1,0.1,0),(3.1,3.1,0),(3.1,0.1,6),(3.1,3.1,6))
b1 = polyhedra_utils.polyhedra(material=n,v=v1,fixed=True) # you can set wire at
b2 = polyhedra_utils.polyhedra(material=n,v=v2,fixed=True)
b3 = polyhedra_utils.polyhedra(material=n,v=v3,fixed=True)
b4 = polyhedra_utils.polyhedra(material=n,v=v4,fixed=True)
wall = polyhedra_utils.polyhedra(material=n,v=v5,fixed=True)
b2.shape.wire=True

O.bodies.append((b1,b2,b3,b4,wall))

polyhedra_utils.fillBox((0.2,0.2,0.2),(2.8,2.8,20),n,seed=1)

O.engines = [
    ForceResetter(),
    InsertionSortCollider([Bo1_Polyhedra_Aabb()]),
    InteractionLoop(
        [Ig2_Polyhedra_Polyhedra_ScGeom()],
        [Ip2_FrictMat_FrictMat_FrictPhys()],
        [Law2_ScGeom_FrictPhys_CundallStrack()] # contact law -- apply forces
    ),
    # GravityEngine(gravity=(0,0,-9.81)),
    NewtonIntegrator(damping=0.5, gravity=(0, 0, -9.81)),
    PyRunner(command='checkUnbalanced()', realPeriod=3, label='checker')
]

O.dt=1e-5

Question information

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Last query:
2019-06-03
Last reply:
2019-06-03
Jan Stránský (honzik) said : #1

Hello,

> i have tried many value of time step

what values (or at least in what range)?

As always in this kind of problem, you can try to increase stiffness.

The repulsive force is computed proportionally to penetration volume, you can try to use thicker walls or true Yade Wall (where the semi-space penetration is computed, not just true intersection of a polyhedron and thin box.

cheers
Jan

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