Re: [Yade-users] [Question #693455]: addForce didnt work for facet
Question #693455 on Yade changed: https://answers.launchpad.net/yade/+question/693455 Status: Open => Answered Jan Stránský proposed the following answer: Hello, 1) please provide a MWE [1], W=working, reproducing your problem (but still keeping it M=minimal). Here, addForces is never called, so you do not apply the force actually and that is the reason why "it just doesnt work"... There can be many reasons, hard even to guess without actual code: - addForces / O.forces.addF is never used / is misused - preStress is 0 (not defined in the provided code) - it just works, just you wrongly interpret it (typically it is not "visible in GUI" but observable according to numerical results) - ... 2) yes [2], in python it would be normal = (v1-v0).cross(v2-v1).normalized() # vertices are v0,v1,v2 so the normal is "right-hand-ruled by v0,v1,v2" cheers Jan [1] https://www.yade-dem.org/wiki/Howtoask [2] https://gitlab.com/yade-dev/trunk/-/blob/master/pkg/common/Facet.cpp#L36 -- You received this question notification because your team yade-users is an answer contact for Yade. ___ Mailing list: https://launchpad.net/~yade-users Post to : yade-users@lists.launchpad.net Unsubscribe : https://launchpad.net/~yade-users More help : https://help.launchpad.net/ListHelp
[Yade-users] [Question #693459]: Python 3 - randomDensePack
New question #693459 on Yade: https://answers.launchpad.net/yade/+question/693459 Hi all, This is a really silly question but I am banging my head in the wall :( After an update in Yade, I am now migrating my codes to Python 3. So far so good. When I use the function randomDensePack with pack.gtsSurface, it works fine. It is possible to see that the pack is dense due to Triaxial test. However, when I use randomDensePack with pack.inSphere the pack I get is not dense It seems to be a simple solution, perhaps due to changes in Python 3 (my guess). = #Forca normal lei de contato coesao e atrito from yade import plot from yade import pack from yade import utils from yade import bodiesHandling import math import random O.materials.append(JCFpmMat(type=1,young=70e9,poisson=0.3,frictionAngle=radians(30),density=2500,tensileStrength=10.7e5,cohesion=10.7e5,jointNormalStiffness=1e5,jointShearStiffness=1e5,jointCohesion=10.7e5,jointFrictionAngle=radians(30),jointDilationAngle=0.0,label='spheres')) O.materials.append(JCFpmMat(type=1,young=70e8,poisson=0.3,frictionAngle=radians(10),density=2000,tensileStrength=0,cohesion=0,jointNormalStiffness=0,jointShearStiffness=0,jointCohesion=0,jointFrictionAngle=radians(0),jointDilationAngle=0.0,label='plates')) ##Radius by Class## size=1 if size==1: rag=0.00238 # rad=0.0003 r=rag # Spheres ag=O.bodies.append( pack.randomDensePack( (pack.inSphere((0,0,r),r)),radius=rad,color=(0,1,0),rRelFuzz=0,material='spheres') ) if size==1: n = 0 #number of spheres to exclude randomically if size==2: n = 96 #number of spheres to exclude randomically if size==3: n = 620 #number of spheres to exclude randomically if size==4: n = 1905 #number of spheres to exclude randomically ##Planes# O.engines=[ ForceResetter(), InsertionSortCollider([Bo1_Sphere_Aabb(),Bo1_Facet_Aabb()]), InteractionLoop( [Ig2_Sphere_Sphere_ScGeom(),Ig2_Facet_Sphere_ScGeom()], [Ip2_JCFpmMat_JCFpmMat_JCFpmPhys(cohesiveTresholdIteration=1)],#xSectionWeibullShapeParameter=4 [Law2_ScGeom_JCFpmPhys_JointedCohesiveFrictionalPM(smoothJoint=False, Key="Wei", recordCracks=True)] ), GlobalStiffnessTimeStepper(active=1,timeStepUpdateInterval=500,timestepSafetyCoefficient=0.5), NewtonIntegrator(damping=0.1,gravity=[0,0,-9.81]), ] from yade import qt qt.View() qt.Controller() -- You received this question notification because your team yade-users is an answer contact for Yade. ___ Mailing list: https://launchpad.net/~yade-users Post to : yade-users@lists.launchpad.net Unsubscribe : https://launchpad.net/~yade-users More help : https://help.launchpad.net/ListHelp
[Yade-users] [Question #693462]: problem in uniaxial test of rocks
New question #693462 on Yade:
https://answers.launchpad.net/yade/+question/693462
Hello:
I have some questions while using Yade to simulate the uniaxial test of rock
material. I do the simulation in 2 steps. In the first step, the packing is
formulated and the packing was sheared in the second step, where the problem
appears. With the increase of the vertical strain, the horizontal stress (the
third column in [3]) can not be well controlled to zero. I wonder what causes
the phenomenon.
Here are the scripts and output results:
[1] scripts for generating the packing:
from yade import pack
O.materials.append(CohFrictMat(young=88.e9,alphaKr=2.0,alphaKtw=0.,poisson=.7,frictionAngle=.0,isCohesive=True,normalCohesion=3.e9,shearCohesion=3.e9,momentRotationLaw=True))
sp = pack.SpherePack()
size = .3
sp.makeCloud(minCorner=(0,0,.05),maxCorner=(size,size,.05),rMean=.005,rRelFuzz=0.2,num=400,periodic=True,seed=1)
sp.toSimulation()
O.cell.hSize = Matrix3(size,0,0, 0,size,0, 0,0,.1)
print len(O.bodies)
for p in O.bodies:
p.state.blockedDOFs = 'zXY'
p.state.mass = 2650 * 0.1 * pi * p.shape.radius**2 # 0.1 = thickness of
cylindrical particle
inertia = 0.5 * p.state.mass * p.shape.radius**2
p.state.inertia = (.5*inertia,.5*inertia,inertia)
O.dt = .5*utils.PWaveTimeStep()
print O.dt
O.engines = [
ForceResetter(),
InsertionSortCollider([Bo1_Sphere_Aabb()]),
InteractionLoop(
[Ig2_Sphere_Sphere_ScGeom6D()],
[Ip2_CohFrictMat_CohFrictMat_CohFrictPhys(
label='cohesiveIp',
setCohesionNow=False)],
[Law2_ScGeom6D_CohFrictPhys_CohesionMoment( # contact law
useIncrementalForm=False,
always_use_moment_law=False,
label='cohesiveLaw')]
),
PeriTriaxController(
dynCell=True,
goal=(-1.e7,-1.e7,0),
stressMask=3,
relStressTol=.001,
maxUnbalanced=.001,
maxStrainRate=(.5,.5,.0),
doneHook='term()',
label='biax'
),
NewtonIntegrator(damping=.2)
]
def term():
#O.engines = O.engines[:3]+O.engines[4:]
print getStress()
print O.cell.hSize
cohesiveIp.setCohesionNow = True
cohesiveIp.setCohesionOnNewContacts = False # if False, only existing
contacts can be cohesive and new contacts are only frictional
cohesiveLaw.always_use_moment_law = False # if True, use bending/twisting
moments at all contacts. If False, compute moments only for cohesive contacts
cohesiveLaw.useIncrementalForm = True # use the incremental formulation to
compute bending and twisting moments
setContactFriction(0.5)
O.cell.trsf=Matrix3.Identity
O.cell.velGrad=Matrix3.Zero
area=0.
for p in O.bodies:
p.state.vel = Vector3.Zero
p.state.angVel = Vector3.Zero
p.state.refPos = p.state.pos
p.state.refOri = p.state.ori
area += pi*p.shape.radius**2
areatol=O.cell.volume/O.cell.hSize[2,2]
void=areatol-area
voidratio=void/area
print voidratio
O.save('5mm_88_2_3g_3g.yade.gz')
O.pause()
O.run();O.wait()
[2] scripts to shear
from minieigen import *
from yade import plot
import numpy as np
import math, random
O.load('5mm_88_2_3g_3g.yade.gz')
biax.doneHook='unaxshear()'
fout = file('5mm_88_2_3g_3g.dat','w')
fout.close()
def output():
fout = open('5mm_88_2_3g_3g.dat','a')
ss = -biax.stress/1.e6
st = -biax.strain
print>>fout,st[0],st[1],ss[0],ss[1]
fout.close()
def unaxshear():
print 'Stress:',utils.getStress()
#print 'Void ratio',getVoidRatio2D()
print 'Press start to shear\n'
O.pause()
biax.goal=(0.,-8.e-2,0.)
biax.stressMask=1
biax.doneHook=''
biax.relStressTol=.001
biax.maxUnbalanced=.001
biax.maxStrainRate=(.5,.5,0)
O.engines +=
[PyRunner(command='output()',iterPeriod=1000,label='outdata',dead = False)]
[3] the output results (the first to fourth columns correspond to strainx,
strainy, stressx, stressy)
-7.52121482369e-07 7.52121482369e-07 9.99913851027 10.0008273603
-0.000752873321006 0.000752873886694 7.15926320142 12.837817399
-0.00150499452053 0.00150499565191 4.31219709936 15.6755667321
-0.00225711572006 0.00225711741712 1.45740355263 18.526142961
-0.00266968416804 0.00300923918233 0.0115157171184 21.5155486273
-0.00273771945847 0.00376136094755 0.00979896515048 24.6663406295
-0.00280666855613 0.00451348271276 0.0033719341489 27.8333521173
-0.00287633923431 0.00526560447797 -0.00654850390782 31.0103413953
-0.00294295053548 0.00601772624319 -0.00336711696265 34.1881098127
-0.00300797298852 0.0067698480084 0.00707226349218 37.3636314747
-0.00307533520998 0.00752196977361 0.00802915923236 40.5352437554
-0.00314524703698 0.00827409153882 -0.00183744269654 43.7050569085
-0.00321386989005 0.00902621330404 -0.00668459677995 46.8844730087
-0.00327917456332 0.00977833506925 0.00270472319407 50.0643941793
-0.00334556010797 0.0105304568345 0.00899177960859 53.2491342812
-0.00341557991373 0.0112825785997 0.001491789509 56.4419088315
-0.00348589116285 0.0120347003649 -0.00683417129809
Re: [Yade-users] [Question #693446]: How to have viscous damping for chainedCylinder
Question #693446 on Yade changed: https://answers.launchpad.net/yade/+question/693446 Status: Open => Answered Bruno Chareyre proposed the following answer: Hi, I have noticed those violent vibrations sometimes and I'm still not sure if it is a bug somewhere or just expected instability due to timestep issues. Anyway, chainedCylinders are deprecated and will probably not interact properly with PFacets. You should use PFacets for both the object and the brush (PFacets include cylinders as a special case). On viscosity: whether it is a bug or a legit numerical instability viscosity will probably not help in solving it. It can make it only worse. If you still want viscosity (because the real brush has some) you'll have to dive and implement it. As you found out creep is really creep: an irreversible Maxwell-kindof viscoplastic process. I hope it helps. Bruno -- You received this question notification because your team yade-users is an answer contact for Yade. ___ Mailing list: https://launchpad.net/~yade-users Post to : yade-users@lists.launchpad.net Unsubscribe : https://launchpad.net/~yade-users More help : https://help.launchpad.net/ListHelp
Re: [Yade-users] [Question #693446]: How to have viscous damping for chainedCylinder
Question #693446 on Yade changed: https://answers.launchpad.net/yade/+question/693446 Rohit John posted a new comment: Thanks for you answer Bruno. I have read that most of the constitutive laws do no have a velocity base damping [1]. Is there a reason why velocity base damping was not implemented? I apologise, I did use gridConnectio/gridNodes to make the brush. I used CylinderConnections to do it. I always get it confused with chainedCylinders. Could you please check if my proposal to implement damping is correct. - Define a material class which includes a damping parameter. Since I am using CylinderConnections I can inherit the class CohFrictMat and name it, say, ViscCohFrictMat - Define a Iphys defining the interaction between two instances of this material class. I can inherit Ip2_CohFrictMat_CohFrictMat_CohFrictPhys() and lets call it Ip2_ViscCohFrictMat_ViscCohFrictMat_ViscCohFrictPhys() - Define a law to define the forces based on the ScGeom6D Igeom and ViscCohFrictPhys() Iphys, and inherit the Law2_ScGeom6D_CohFrictPhys_CohesionMoment() [1] https://yade-dem.org/doc/formulation.html?highlight=damping#numerical-damping -- You received this question notification because your team yade-users is an answer contact for Yade. ___ Mailing list: https://launchpad.net/~yade-users Post to : yade-users@lists.launchpad.net Unsubscribe : https://launchpad.net/~yade-users More help : https://help.launchpad.net/ListHelp
[Yade-users] [Question #693469]: questions about plotDirections
New question #693469 on Yade: https://answers.launchpad.net/yade/+question/693469 Hi, I have few questions about plotDirections[1] : 1. Every time I use utils.plotDirections() I can get a figure, my stupid question is how to save that figure automatically during the simulation? 2. There are two kinds of sphere particles in my model by using different materials (e.g., Mat1 and Mat2), the plotDirections() plots the distribution of overall contacts. What if I want to plot Mat1-Mat1, Mat1-Mat2 contacts distributions seperately? 3. Just a curiosity. Normally in fabric analysis, papers like to make the rose figure symmetric by plotting a pair of contact vectors for each interaction (i.e., one vector from sphere1 to sphere2 and another from sphere2 to sphere1). So I wonder if it can be done using plotDirections()? 4. May I ask yade developers what is the idea to plot the rose diagram of 3D vectors to a plane (let's say xy plane)? Project all vectors to the xy plane to gain the corresponding 2D vectors and draw the 2D rose diagram? I am asking this because if question2 and 3 couldn't be solved using the build-in functions in yade, then I will output the contact vectors and draw these diagrams in python. Thanks! Leonard [1]https://yade-dev.gitlab.io/trunk/yade.utils.html?highlight=plotdirections#yade.utils.plotDirections -- You received this question notification because your team yade-users is an answer contact for Yade. ___ Mailing list: https://launchpad.net/~yade-users Post to : yade-users@lists.launchpad.net Unsubscribe : https://launchpad.net/~yade-users More help : https://help.launchpad.net/ListHelp
