New question #692351 on Yade:
https://answers.launchpad.net/yade/+question/692351
Dear all,
I'm trying to simulate three-point bending test in Yade.
I have prepared a sample with random dense pack.
In order to apply the load as a piston, I need to have a plate with 3mm in
width and 50mm length parallel to xz plane in the middle of the beam.
and another two plates as rollers with the same dimensions at the bottom left
and right locations?
How can I add a plate with a specific dimension?
Previously I have used facetcylinder to apply load as well as to use as rollers.
Now I need to use a single plate instead of this facet cylinder. could you
please tell me how to do that?
this is my existing code,
# -*- coding: utf-8 -*-
# Code for three point bending test with crack mouth opening displacement and
deflection
#Developed by S.M.C.U. Senanayake, Department of Civil Engineering, Monash
University, Australia
from yade import pack
############################################
### DEFINING VARIABLES AND MATERIALS ###
############################################
from yade import pack, plot,qt,ymport
import os
import csv
# Damping:
damp=0.7
stabilityThreshold=0.001 # we test unbalancedForce against this value in
different loops (see below)
# material parameters
#young = 6.75e8
#poisson = .2
#frictionAngle = 0.6
#sigmaT = 1.5e6
#epsCrackOnset = 16.4e-3
#relDuctility = 1.05
#density = 2600
young = 3e9
poisson = .3
frictionAngle = 0.5
sigmaT = .3e6
epsCrackOnset = .9e-3
relDuctility = 30
density = 2600
# prestress
# axial strain rate
rate=0.01 # loading rate (strain rate)
# stress path
'''
# 3 point bending test sample preparation parameters
L= length of the sample
W= width of the sample
H= height of the sample
C=clearance from two ends(canteliver length
A= width of the notch
B= height of the notch
R=radius of the rollers/piston(radius of facet clyinder) all mm s (10^-3) scale
Length along x axis, height along y axis and width along z axis
'''
#mn,mx=Vector3(0,0,0),Vector3(1,1,1) # corners of the initial packing
L=500e-3
W=50e-3
H=100e-3
C=50e-3
A=3e-3
B=50e-3
R=7e-3
psdmean=3e-3
rmin=1.5*psdmean
prepared=0
v=.1 # applied velocity on piston
concMat=O.materials.append(CpmMat(young=young,poisson=poisson,density=density,damLaw=1,frictionAngle=frictionAngle,
sigmaT=sigmaT,epsCrackOnset=epsCrackOnset,neverDamage=False,label='concrete',relDuctility=relDuctility,))
frictMat =
O.materials.append(CpmMat(young=100*young,poisson=poisson,frictionAngle=0,sigmaT=0,epsCrackOnset=epsCrackOnset,relDuctility=1.0001,neverDamage=True,density=3000,label='walls'))
if prepared<0.5:
pred=pack.inAlignedBox((0,0,0),(L,H,W))-pack.inAlignedBox((.5*(L-A),0,0),(.5*(L+A),B,W))
#SpherePack=pack.randomDensePack(pred,spheresInCell=11000,radius=psdmean,rRelFuzz=0.2,color=(0,0,1),material=concMat,returnSpherePack=True)
SpherePack=pack.randomDensePack(pred,spheresInCell=500,radius=psdmean,rRelFuzz=0.2,color=(0,0,1),material=concMat,returnSpherePack=True)
sand=SpherePack.toSimulation() # assign all particles to sand object
else:
O.bodies.append(ymport.textExt('tpb_sample.txt',format='x_y_z_r',material=concMat))
print ('I have previously prepared packing!!')
for b in O.bodies:
if isinstance(b.shape,Sphere):
b.shape.color = (0.2,0.6,0.6)# give a colour
# In order to extract the ids of each particle in the left and right hand
corner of the notch and make a list out of them
leftids=[]
for i in O.bodies:
if i.state.pos[0]>(0.5*(L-A)-2*rmin) and i.state.pos[0]<(0.5*(L-A)):
if i.state.pos[1]>0 and i.state.pos[1]<(2*rmin):
i.shape.color=(1,0,0)
leftids.append(i.id)
#left=[O.bodies[i] in sand]
rightids=[]
c=0
for i in O.bodies:
if i.state.pos[0]>(0.5*(L+A)) and i.state.pos[0]<(0.5*(L+A)+2*rmin):
if i.state.pos[1]>0 and i.state.pos[1]<(2*rmin):
i.shape.color=(1,0,0)
c=c+1
print i
print i.id
rightids.append(i.id)
#right=[O.bodies[i] in sand]
print c
print rightids
#print right
# assign to a lh object all particles in the left hand side interested region
of the notch
lh = [O.bodies[s] for s in sand if (O.bodies[s].state.pos[0]>(0.5*(L-A)-2*rmin)
and O.bodies[s].state.pos[0]<(0.5*(L-A)) and O.bodies[s].state.pos[1]>0 and
O.bodies[s].state.pos[1]<(2*rmin))]
rh=[O.bodies[s] for s in sand if (O.bodies[s].state.pos[0]>(0.5*(L+A)) and
O.bodies[s].state.pos[0]<(0.5*(L+A)+2*rmin) and O.bodies[s].state.pos[1]>0 and
O.bodies[s].state.pos[1]<(2*rmin))]
for i in rh:
print i.id
# assign global variable to total numbe rof particles in each block
global left_part
left_part=len(leftids)
global right_part
right_part=len(rightids)
piston=O.bodies.append(geom.facetCylinder(center=(.5*L,H+R,.5*W),radius=R,height=W,orientation=Quaternion((0,
0, 1), pi/2),segmentsNumber=20,wire=False,material=frictMat)) #piston radius
is 15mm
left_roller=O.bodies.append(geom.facetCylinder(center=(C,-R,.5*W),radius=R,height=W,orientation=Quaternion((0,
0, 1), pi/2),segmentsNumber=20,wire=False,material=frictMat))
right_roller=O.bodies.append(geom.facetCylinder(center=(L-C,-R,.5*W),radius=R,height=W,orientation=Quaternion((0,
0, 1), pi/2),segmentsNumber=20,wire=False,material=frictMat))
newton=NewtonIntegrator(damping=damp)
enlargeFactor=1.5
for b in O.bodies:
if isinstance(b.shape,Sphere):
b.shape.color = (0.2,0.6,0.6)
print len(O.bodies)
O.engines=[
ForceResetter(),
InsertionSortCollider([
Bo1_Sphere_Aabb(aabbEnlargeFactor=enlargeFactor,label='bo1s'),
Bo1_Facet_Aabb()
]),
InteractionLoop(
[
Ig2_Sphere_Sphere_ScGeom(interactionDetectionFactor=enlargeFactor,label='ig2ss'),
Ig2_Facet_Sphere_ScGeom()
],
[
Ip2_CpmMat_CpmMat_CpmPhys(cohesiveThresholdIter=O.iter+5),
Ip2_FrictMat_CpmMat_FrictPhys(),
Ip2_FrictMat_FrictMat_FrictPhys(),
],
[
Law2_ScGeom_CpmPhys_Cpm(),
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)
#TranslationEngine(ids=[piston.id],translationAxis=[0,0,1],velocity=1),
GlobalStiffnessTimeStepper(active=1,timeStepUpdateInterval=100,timestepSafetyCoefficient=0.3),
#VTKRecorder(fileName='/home/ud/vtkdata/3pb_test', recorders=['all'],
iterPeriod=100),
PyRunner(iterPeriod=1,command='apply()',label='apply'),
PyRunner(iterPeriod=1,command='addPlotData()',label='graph'),
#PyRunner(iterPeriod=50,command='pr()',label='ph'),
newton,
#CpmStateUpdater(iterPeriod=100),
]
#Display spheres with 2 colors for seeing rotations better
Gl1_Sphere.stripes=0
qtr=yade.qt.Renderer()
qtr.bgColor=(1,1,1)
yade.qt.Controller(), yade.qt.View()
O.step()
bo1s.aabbEnlargeFactor=ig2ss.interactionDetectionFactor=1.
cylinderIds=[]
for i in range(0,len(piston)):
cylinderIds.append(piston[i])
#print piston[i]
#print cylinderIds
def apply():
for i in range(0,len(piston)):
O.bodies[piston[i]].state.vel[1]=-v
# a function to find crack mouth opening displacement
def cmod():
sumlh=0
sumrh=0
for i in lh:
dp_left=i.state.pos[0]-i.state.refPos[0]# left displacment
sumlh+=dp_left # addig all the displacement in x direction
components
for j in rh:
dp_right=j.state.pos[0]-j.state.refPos[0]
sumrh+=dp_right
d1=sumlh/left_part # average displacment in left hand side of the notch
d2=sumrh/right_part
cmodi=abs(d1)+abs(d2) # cmod by adding right ahand side and left hand
side
return (cmodi)
def addPlotData():
f_2=utils.sumForces(ids=cylinderIds,direction =(0,1,0))# measure total
force induced on the cylinder
delta_z=v*O.time
crackopen=cmod()
#print f_2
plot.addData(t = O.time,f_2 = f_2,delta_z=delta_z,crackopen=crackopen)
#O.engines=O.engines+[PyRunner(command='pr()',iterPeriod=50)]
def pr():
presentcohesive_count = 0
for i in O.interactions:
if hasattr(i.phys, 'isCohesive'):
if i.phys.isCohesive == 0:
presentcohesive_count+=1
a=i.id1
b=i.id2
O.bodies[a].shape.color = (1,0,0)
O.bodies[b].shape.color = (1,0,0)
#print (i.id1, "-", i.id2)
noncohesive_count=presentcohesive_count
#O.engines=O.engines+[TranslationEngine(ids=[piston.id],translationAxis=[0,0,1],velocity=1)]
#plot.plots={'delta_z':('f_2',), 'crackopen':('f_2 ')}
plot.plots={'crackopen':('f_2',)}
plot.plot()
#print (len(O.bodies))
from yade import qt
qt.Controller()
qt.View()
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