yade-users team mailing list archive

[jacopo <question673436@xxxxxxxxxxxxxxxxxxxxx>]

New question #673436 on Yade:
https://answers.launchpad.net/yade/+question/673436

hi , i'm sorry but i need to take again your time.

I ' m trying to assemble same particles together without clumping them ( i don't want a rigid body). To do this i'm using cohesive model. The assembled particles will hit a "barrier" made by sphere elements (its material is built through Frictmat)
Not all the particles seems to be connected to the others when the assemble(its material is cohFrictmat) hits the barrier. In particular in my real simulation i can notice that some particles (the most far) continue their movement like they are not connected to anything. Others particles break from the assembled structure and continue their movement somewhere. I tryied to play with the material parameters but i didn't see a great change. The only parameters that seems working is the spheres radius of the assemble. More the radius is low more seems the cohesion between particles. The problem is that if i get a too low radius, my simulation has too many bodies and last to much time (and i don't know if lowering the radius i will really fix the problem). 

-> how can i fix this problem?

-> I know that after a certain stress it ' s normal that the assemble starts to break, but which is the parameters that govern this phenomenon?
   
I post here a simple script that should facilitate the comprension of my problem: i don't want that the side particles will go forward their direction, but i want that they stay together. 
thanks for your time.


#############################################################
#############################################################

from yade import pack, plot
from yade import export, ymport
from yade import utils
from yade import qt
from yade import plot
import sys,time


#####################
####### OBJ #######
#####################

O.materials.append(CohFrictMat(young=30000e6,poisson=0.3,density=3600,frictionAngle=radians(30),isCohesive=True,normalCohesion=1e100000000,shearCohesion=1e10000000,momentRotationLaw=True,etaRoll=0.1,label='spheres'))

pred=pack.inAlignedBox((0.05,-0.5,-0.05),(0.1,0.5,0.05))
spheres=pack.regularHexa(pred,radius=0.01,gap=0)
O.bodies.append(spheres)

for b in O.bodies:
   b.state.vel=(-18,0,0)

################
##box2 material##
################

idCA=FrictMat(density=2227,frictionAngle=radians(0.5),label='CA',young=30e9,poisson=0.15)
O.materials.append(idCA)

############################
####### BOX 2 ##############
############################

O.bodies.append(geom.facetBox((-0.3,0,0),(0.2,0.2,0.1),wallMask=29)) 

#################
##soil material##
#################

idSoil=FrictMat(density=1500,frictionAngle=radians(29),label='soil',young=11277647.5,poisson=0.21)	
O.materials.append(idSoil)

############################

pred=pack.inAlignedBox((-0.5,-0.2,-0.1),(-0.1,0.2,0.1))
spheres=pack.regularHexa(pred,radius=0.02,gap=0)
O.bodies.append(spheres)

###################
###################
###################

O.engines=[
   ForceResetter(),
   InsertionSortCollider([Bo1_Sphere_Aabb(),Bo1_Facet_Aabb()]),
InteractionLoop(
[Ig2_Sphere_Sphere_ScGeom6D(),Ig2_Facet_Sphere_ScGeom()],
[Ip2_FrictMat_FrictMat_FrictPhys(),
Ip2_CohFrictMat_CohFrictMat_CohFrictPhys (setCohesionNow=True,label="cohesiveIp")],
[Law2_ScGeom_FrictPhys_CundallStrack(),
Law2_ScGeom6D_CohFrictPhys_CohesionMoment(useIncrementalForm=True,label='cohesiveLaw')]
),
 NewtonIntegrator(gravity=(0,0,-9.81)),
]

O.dt=0.8*PWaveTimeStep()
O.saveTmp()




-- 
You received this question notification because your team yade-users is
an answer contact for Yade.