[Yade-users] [Question #654914]: convergence issue! using unbalancedForce()
New question #654914 on Yade:
https://answers.launchpad.net/yade/+question/654914
Dear Friends,
I am not sure why my below script, does not converge, even by increasing the
micro parameters such as friction angle, the simulation does not reach to
target and gives me flat surface of grains instead of a heap - it is a time
consuming process . can you please advise me where is my mistake?
#!/usr/bin/python
from yade import pack,utils, qt, plot
pred = pack.inAlignedBox((0,0,0),(0.067,0.067,0.067))
#create material.
#soil1 =
CohFrictMat(young=30e7,poisson=0.3,frictionAngle=radians(30),density=2600.0,normalCohesion=10e9,
shearCohesion=80e9,alphaKr=0.15,label='soil')
soil1 =
CohFrictMat(alphaKr=0.15,young=30e9,poisson=0.4,density=2600,frictionAngle=radians(36.5),momentRotationLaw=True,etaRoll=0.3,label='spheres')
#color=(1,0,0) red color
#soil1 =
FrictMat(alphaKr=1.7,young=30e6,poisson=0.3,frictionAngle=radians(30),density=2600.0,etaRoll=.4,label='soil')
O.materials.append(soil1)
O.bodies.append(utils.wall(0,axis=1,sense=1))
O.materials.append(CohFrictMat(young=30e6,poisson=0.3, frictionAngle =
radians(30) , label='wallmat'))
#O.materials.append(FrictMat(young=30e9,poisson=0.3, frictionAngle =
radians(30) , label='wallmat'))
wallmat = O.materials[-1]
spheres=SpherePack()
spheres=pack.randomDensePack(pred,radius=.0025,rRelFuzz=0,material='soil',spheresInCell=1000,color=(1,0,0),returnSpherePack=True)
spheres.toSimulation()
#O.bodies.append(spheres)
#
#
O.engines=[
ForceResetter(),#reset forces
InsertionSortCollider([Bo1_Wall_Aabb(),Bo1_Sphere_Aabb()]),
InteractionLoop(
[Ig2_Sphere_Sphere_ScGeom6D(),Ig2_Wall_Sphere_ScGeom()], # collision geometry
[Ip2_CohFrictMat_CohFrictMat_CohFrictPhys(),
Ip2_FrictMat_FrictMat_FrictPhys ()],# collision "physics"
[Law2_ScGeom6D_CohFrictPhys_CohesionMoment(),Law2_ScGeom_FrictPhys_CundallStrack()]
# contact law -- apply forces
),
# apply gravity force to particles
# damping: numerical dissipation of energy
NewtonIntegrator(damping=0.4,gravity=(0,-9.81,0)),
#qt.SnapshotEngine(fileBase='3d-',iterPeriod=200,label='snapshot'),
# this engine will be called after 2 steps, only once
PyRunner(command='checkUnbalanced()',realPeriod=50,label='checker'),
PyRunner(command='addPlotData()',iterPeriod=100)
]
print 'Number of elements: ', len(O.bodies)
print 'Box Volume: '
print '8000,unbalancedForce()<1e-1,0.0005,
alphaKr=0.15,young=30e9,poisson=0.4,density=2600,frictionAngle=radians(36.5),momentRotationLaw=True,etaRoll=0.3,'
O.trackEnergy=True
# set timestep to a fraction of the critical timestep
# the fraction is very small, so that the simulation is not too fast
# and the motion can be observed
O.dt=2.1*utils.PWaveTimeStep()
#makeVideo(snapshot.snapshots,'3d.mpeg',fps=10,bps=1)
# save the simulation, so that it can be reloaded later, for experimentation
#O.saveTmp()0
#checker.command='stopUnloading()'
def checkUnbalanced():
if unbalancedForce()<1e-2:
print('Reached target , stopping')
O.pause()
plot.saveDataTxt('FrictMat,e-2repose10degree,r=.5,0, damping=
0.5.txt.bz2')
plot.saveDataTxt('FrictMat,e-2repose10degree,r=.5,0, damping= 0.5.txt')
#plot.saveDataTxt('modi.data.bz2')
# plot.saveGnuplot('bbb') is also possible
# collect history of data which will be plotted
def addPlotData():
# each item is given a names, by which it can be the unsed in plot.plots
# the **O.energy converts dictionary-like O.energy to plot.addData arguments
plot.addData(i=O.iter,unbalanced=unbalancedForce(),**O.energy)
#O.save('Modifiedd.txt.bz2')
#while 1:
#O.run(100,True)
#if unbalancedForce()<1e-5:
#break
plot.plots={'i':('unbalanced',None,O.energy.keys)}
plot.plot()
O.saveTmp()
#plot.saveDataTxt('2')
from yade import qt
qt.View()
#O.run()
#from yade import qt
#qt.View()
#O.run()
# this function is called when the simulation is finished
#def finish():
# snapshot is label of qt.SnapshotEngine
# the 'snapshots' attribute contains list of all saved files
#makeVideo(snapshot.snapshots,'3d.mpeg',fps=10,bps=1)
#O.pause()
yade.qt.Controller();
# set parameters of the renderer, to show network chains rather than particles
# these settings are accessible from the Controller window, on the second tab
("Display") as well
#rr=yade.qt.Renderer()
#rr.shape=False
#rr.intrPhys=True
plot.saveDataTxt('reposefric,.2,17,17,.004mm,young=30e6,poisson=0.3,frictionAngle=radians(30),density=2600.0')
Thanks,
Seti
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Re: [Yade-users] [Question #654914]: convergence issue! using unbalancedForce()
Question #654914 on Yade changed:
https://answers.launchpad.net/yade/+question/654914
Status: Open => Answered
Chareyre proposed the following answer:
Hi, I'm guessing you expect a heap because of the rolling moments (?). Did
you check if moments were indeed computed and non-zero?
Bruno
Le 2 août. 2017 15:53, "Seti" a
écrit :
New question #654914 on Yade:
https://answers.launchpad.net/yade/+question/654914
Dear Friends,
I am not sure why my below script, does not converge, even by increasing
the micro parameters such as friction angle, the simulation does not reach
to target and gives me flat surface of grains instead of a heap - it is a
time consuming process . can you please advise me where is my mistake?
#!/usr/bin/python
from yade import pack,utils, qt, plot
pred = pack.inAlignedBox((0,0,0),(0.067,0.067,0.067))
#create material.
#soil1 = CohFrictMat(young=30e7,poisson=0.3,frictionAngle=
radians(30),density=2600.0,normalCohesion=10e9,
shearCohesion=80e9,alphaKr=0.15,label='soil')
soil1 = CohFrictMat(alphaKr=0.15,young=30e9,poisson=0.4,
density=2600,frictionAngle=radians(36.5),momentRotationLaw=True,
etaRoll=0.3,label='spheres')
#color=(1,0,0) red color
#soil1 = FrictMat(alphaKr=1.7,young=30e6,poisson=0.3,
frictionAngle=radians(30),density=2600.0,etaRoll=.4,label='soil')
O.materials.append(soil1)
O.bodies.append(utils.wall(0,axis=1,sense=1))
O.materials.append(CohFrictMat(young=30e6,poisson=0.3, frictionAngle =
radians(30) , label='wallmat'))
#O.materials.append(FrictMat(young=30e9,poisson=0.3, frictionAngle =
radians(30) , label='wallmat'))
wallmat = O.materials[-1]
spheres=SpherePack()
spheres=pack.randomDensePack(pred,radius=.0025,rRelFuzz=0,
material='soil',spheresInCell=1000,color=(1,0,0),returnSpherePack=True)
spheres.toSimulation()
#O.bodies.append(spheres)
#
#
O.engines=[
ForceResetter(),#reset forces
InsertionSortCollider([Bo1_Wall_Aabb(),Bo1_Sphere_Aabb()]),
InteractionLoop(
[Ig2_Sphere_Sphere_ScGeom6D(),Ig2_Wall_Sphere_ScGeom()],
# collision geometry
[Ip2_CohFrictMat_CohFrictMat_CohFrictPhys(),
Ip2_FrictMat_FrictMat_FrictPhys ()],# collision "physics"
[Law2_ScGeom6D_CohFrictPhys_
CohesionMoment(),Law2_ScGeom_FrictPhys_CundallStrack()] # contact law --
apply forces
),
# apply gravity force to particles
# damping: numerical dissipation of energy
NewtonIntegrator(damping=0.4,gravity=(0,-9.81,0)),
#qt.SnapshotEngine(fileBase='
3d-',iterPeriod=200,label='snapshot'),
# this engine will be called after 2 steps, only once
PyRunner(command='checkUnbalanced()',realPeriod=
50,label='checker'),
PyRunner(command='addPlotData()',iterPeriod=100)
]
print 'Number of elements: ', len(O.bodies)
print 'Box Volume: '
print '8000,unbalancedForce()<1e-1,0.0005, alphaKr=0.15,young=30e9,
poisson=0.4,density=2600,frictionAngle=radians(36.5),momentRotationLaw=True,
etaRoll=0.3,'
O.trackEnergy=True
# set timestep to a fraction of the critical timestep
# the fraction is very small, so that the simulation is not too fast
# and the motion can be observed
O.dt=2.1*utils.PWaveTimeStep()
#makeVideo(snapshot.snapshots,'3d.mpeg',fps=10,bps=1)
# save the simulation, so that it can be reloaded later, for experimentation
#O.saveTmp()0
#checker.command='stopUnloading()'
def checkUnbalanced():
if unbalancedForce()<1e-2:
print('Reached target , stopping')
O.pause()
plot.saveDataTxt('FrictMat,e-2repose10degree,r=.5,0, damping=
0.5.txt.bz2')
plot.saveDataTxt('FrictMat,e-2repose10degree,r=.5,0, damping=
0.5.txt')
#plot.saveDataTxt('modi.data.bz2')
# plot.saveGnuplot('bbb') is also possible
# collect history of data which will be plotted
def addPlotData():
# each item is given a names, by which it can be the unsed in plot.plots
# the **O.energy converts dictionary-like O.energy to plot.addData
arguments
plot.addData(i=O.iter,unbalanced=unbalancedForce(),**O.energy)
#O.save('Modifiedd.txt.bz2')
#while 1:
#O.run(100,True)
#if unbalancedForce()<1e-5:
#break
plot.plots={'i':('unbalanced',None,O.energy.keys)}
plot.plot()
O.saveTmp()
#plot.saveDataTxt('2')
from yade import qt
qt.View()
#O.run()
#from yade import qt
#qt.View()
#O.run()
# this function is called when the simulation is finished
#def finish():
# snapshot is label of qt.SnapshotEngine
# the 'snapshots' attribute contains list of all saved files
#makeVideo(snapshot.snapshots,'3d.mpeg',fps=10,bps=1)
#O.pause()
yade.qt.Controller();
# set parameters of the renderer, to show network chains rather than
particles
# these settings are accessible from the Controller window, on the second
tab ("Display") as well
#rr=yade.qt.Renderer()
#rr.shape=False
#rr.intrPhys=True
plot.saveDataTxt('reposefric,.2,17,17,.
Re: [Yade-users] [Question #654914]: convergence issue! using unbalancedForce()
Question #654914 on Yade changed: https://answers.launchpad.net/yade/+question/654914 Status: Answered => Open Seti is still having a problem: Hi Bruno, Thanks for your response.how I can record moments? also I changed material property to cohesive one as per below: soil1 = CohFrictMat(young=30e6,poisson=0.4,frictionAngle=radians(36.5),density=2600.0,normalCohesion=1e5, shearCohesion=.3e5,alphaKr=0.15,etaRoll=0.3,label='soil') now the sample explodes. can you please advise me how I can fix it? thanks, Seti -- 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 #654914]: convergence issue! using unbalancedForce()
Question #654914 on Yade changed: https://answers.launchpad.net/yade/+question/654914 Status: Open => Answered Robert Caulk proposed the following answer: Hello, I imagine your simulation is not stable because you are using a timestep > maxAllowable: O.dt=2.1*utils.PWaveTimeStep() You need to use a fraction of the PWave informed time step to maintain stability [1]. Otherwise you are integrating blindly :-) [1]https://yade-dem.org/doc/formulation.html#stability-considerations -- 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
