Re: [Yade-users] [Question #697610]: How to get the acceleration of body
Question #697610 on Yade changed: https://answers.launchpad.net/yade/+question/697610 Status: Answered => Solved Leonard confirmed that the question is solved: Thanks Jérôme Duriez, that solved my question. -- 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 #697642]: Many errors with PeriodicFlowEngine
New question #697642 on Yade:
https://answers.launchpad.net/yade/+question/697642
After deleting some particles, I encountered a lot of problems in the
PeriodicFlowEngine. Such as:
(1) GS did not converge in 20k iterations (maybe because the reference pressure
is 0?);
(2) segmentation fault (core dumped);
(3) Periodicity is broken;
(4) CHOLMOD warning: matrix not positive definite. file:
../Supernodal/t_cholmod_super_numeric.c line: 911
something went wrong in Cholesky factorization, use LDLt as fallback this time1
For errors (3) and (4), I have solved it by changing the value of
PeriodicFlowEngine.duplicateThreshold and the PeriodicFlowEngine.useSolver.
For errors (1) and (2), I spent a lot of time and tried a lot, but I still
can't solve them. Please help me!
I have searched for the answers about the PeriodicFlowEngine. I concluded that
since there is no boundary condition for periodic boundary conditions, the
PeriodicFlowEngine does not need to set boundary conditions，that is, it does
not need to set the bndCondIsPressure, bndCondValue, boundaryUseMaxMin. As I
want to achieve a similar simulation like the paper " A discrete numerical
model involving partial fluid-solid coupling to describe suffusion effects in
soils "[1], In short, it is to achieve the fluid flow from top to bottom under
a certain pressure gradient, and no fluid flows out from the side, and some
particles are removed during the calculation. So I just need to apply a
macroscopic pressure gradient by flow.gradP=Vector3(0, i,0), where i is the
macroscopic pressure gradient. Is that right?
The errors (1) and (2) still exist, this is my simplified code:
##__ First section, generate sample_
from __future__ import print_function
from yade import pack, qt, plot
from math import *
nRead=readParamsFromTable(
## model parameters
num_spheres=100,
targetPorosity= .4,
confiningPressure=-10,
## material parameters
compFricDegree=15,#contact friction during the confining phase
finalFricDegree=30,#contact friction during the deviatoric loading
young=2e8,
poisson=.2,
density=2600,
alphaKr=7.5,
alphaKtw=0,
competaRoll=.22,
finaletaRoll=.22,
etaTwist=0,
normalCohesion=0,
shearCohesion=0,
## fluid parameters
fluidDensity=1000,
dynamicViscosity=.001,
## control parameters
damp=0,
stabilityThreshold=.001,
## output specifications
filename='suffusion',
unknowOk=True
)
from yade.params.table import *
O.periodic=True
O.cell.hSize=Matrix3(1,0,0, 0,1,0, 0,0,1)
# create materials for spheres
#shear strength is the sum of friction and adhesion, so the
momentRotationLaw=True
O.materials.append(CohFrictMat(alphaKr=alphaKr,alphaKtw=alphaKtw,density=density,etaRoll=competaRoll,etaTwist=etaTwist,frictionAngle=radians(compFricDegree),momentRotationLaw=True,normalCohesion=normalCohesion,poisson=poisson,shearCohesion=shearCohesion,young=young,label='spheres'))
# generate particles packing
sp=pack.SpherePack()
sp.makeCloud((0,0,0),(1,1,1),-1,0.,num_spheres,False, 0.95,seed=1)
sp.toSimulation(material='spheres')
O.engines=[
ForceResetter(),
InsertionSortCollider([Bo1_Sphere_Aabb()]),
InteractionLoop(
[Ig2_Sphere_Sphere_ScGeom6D()],
[Ip2_CohFrictMat_CohFrictMat_CohFrictPhys(label='contact',setCohesionNow=False,setCohesionOnNewContacts=False)],
[Law2_ScGeom6D_CohFrictPhys_CohesionMoment(useIncrementalForm=True,always_use_moment_law=True)],
),
PeriodicFlowEngine(dead=1,label="flow"),#introduced as a dead engine
for the moment, see 2nd section
GlobalStiffnessTimeStepper(active=1,timeStepUpdateInterval=100,timestepSafetyCoefficient=0.8),
PeriTriaxController(label='triax',
# specify target values and whether they are strains or stresses
goal=(confiningPressure,confiningPressure,confiningPressure),
stressMask=7,
# type of servo-control, the strain rate isn't determined, it
shloud check the unbalanced force
dynCell=True,maxStrainRate=(10,10,10),
# wait until the unbalanced force goes below this value
maxUnbalanced=stabilityThreshold,relStressTol=1e-3,
doneHook='compactionFinished()'
),
NewtonIntegrator(damping=0)
]
import sys
def compactionFinished():
# after sample preparation, save the state
O.save('compactedState'+filename+'.yade.gz')
print('Compacted state saved', 'porosity', porosity())
# next time, called python command
triax.doneHook=''
O.pause()
O.run()
O.wait()
#B. Activate flow engine
flow.dead=0
flow.defTolerance=-1
flow.meshUpdateInterval=-1
flow.useSolver=0
flow.permeabilityFactor=1
flow.viscosity=10
flow.gradP=Vector3(0,1,0)
flow.duplicateThreshold=0.3
flow.updateTriangulation=True
O
Re: [Yade-users] [Question #697524]: When I run my code, MatplotlibDeprecationWarning appears
Question #697524 on Yade changed: https://answers.launchpad.net/yade/+question/697524 Status: Answered => Solved Zhicheng Gao confirmed that the question is solved: Thank you, Jérôme Duriez , the version used is yade-2021-06-08.git- 4852d56 -- 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 #697638]: Using thermal engine for a dry granular flow
Question #697638 on Yade changed: https://answers.launchpad.net/yade/+question/697638 Status: Open => Answered Robert Caulk proposed the following answer: Hello, Yes, here is an example script only using conduction between grains [1]. Cheers, Robert [1]https://gitlab.com/yade- dev/trunk/-/blob/master/examples/ThermalEngine/conductionVerification.py -- 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 #697524]: When I run my code, MatplotlibDeprecationWarning appears
Question #697524 on Yade changed:
https://answers.launchpad.net/yade/+question/697524
Status: Open => Answered
Jérôme Duriez proposed the following answer:
Hi,
This warning is because we did not yet update (in YADE source code) our
use of a external library, for plotting "YADE" figures. You can safely
ignore it.
(Please specify your YADE version next time, and try to minimalize your
script: the following 4 lines are enough to illustrate the behavior
from yade import plot
plot.addData(x=0,y=0)
plot.plots={'x':'y'}
plot.plot()
)
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[Yade-users] [Question #697638]: Using thermal engine for a dry granular flow
New question #697638 on Yade: https://answers.launchpad.net/yade/+question/697638 Hello, Is there any possibiility to use thermal engine for a dry granular flow only ? ( modelling only conduction at contacts between moving grains). >> putting fluid viscosity = 0 ?? Regards, V. -- 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 #697597]: PeriIsoCompressor.sigma different from getStress()
Question #697597 on Yade changed: https://answers.launchpad.net/yade/+question/697597 Status: Open => Answered Jérôme Duriez proposed the following answer: Hi, What is sure is that you eventually comparing two stress expressions that are quite different: - PIC uses some totalForceInVolume [*] expression I'm totally unfamiliar with (=> which I can not justify at the moment / ever ?) - getStress is the classical Love-Weber formula. Please open an issue about that engine, especially if you think there is another issue about unbalanced force test (from another discussion) [*] https://gitlab.com/yade- dev/trunk/-/blob/4852d56018376a2d1c2f6e3812bf031cc44d645b/pkg/dem/PeriIsoCompressor.cpp#L53 and below -- 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 #697597]: PeriIsoCompressor.sigma different from getStress()
Question #697597 on Yade changed: https://answers.launchpad.net/yade/+question/697597 Jan Stránský posted a new comment: Hello, confirming the issue. If I continue, the PIC mean stress remains constant, while getStress mean stress is growing, have a try. Maybe it is equal for unbalanced force = 0? (just brainstorming) Also I am not sure is PeriIsoCompressor is maintained or not, have a look at PeriTriaxController. Cheers Jan -- 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 #697600]: Contact (dilation) angle between particles
Question #697600 on Yade changed: https://answers.launchpad.net/yade/+question/697600 Status: Open => Needs information Jan Stránský requested more information: Hello, > I hope this is clear for you. No, sorry, the question is very (and actually more and more) confusing.. How is "contact angle using here means dilation angle (ψ)" from #2 related to "the contact angle described here" from #3? The #3 definition is really an angle (or vector in 3D) of the interaction. You have many interactions, access to the data, you can easily do whatever with the data, e.g. output a distribution. The #2 definition is some macroscopic dimensionless quantity which is called angle "by chance" because the value can be interpreted as an angle in a graph. (similarly to the friction angle). AFAIK ψ is a ratio of volumetric strain and shear strain. How would you / do you want to define it for one contact / region (to make a distribution)? > if there are two particles of the same size ... any difference from the case of different size? > ... horizontal ... would be 90 degrees. ... right on top of the other one ... would be 0 degrees. How is this clear purely geometric meaning related to dilation angle (ψ) (volumetric strain / shear strain)? Please make clear what you want. Cheers Jan -- 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 #697600]: Contact (dilation) angle between particles
Question #697600 on Yade changed: https://answers.launchpad.net/yade/+question/697600 Chien-Cheng Hung gave more information on the question: Just for further clarification. In 2D, if there are two particles of the same size in contact with each other in the horizontal direction, then the contact angle between these two particles would be 90 degrees. Similarly, if the one is right on top of the other one, then the contact angle would be 0 degrees. The contact angle described here is what I want to output as a distribution. I can imagine it would be a bit tricky for a 3D simulation since there are some vector issues... Chien-Cheng -- 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 #697600]: Contact (dilation) angle between particles
Question #697600 on Yade changed: https://answers.launchpad.net/yade/+question/697600 Status: Needs information => Open Chien-Cheng Hung gave more information on the question: Hi, The contact angle using here means dilation angle (ψ). The value of ψ=0 corresponds to the volume that preserves deformation while in shear. Since the angle of dilation (ψ) controls the amount of plastic volumetric strain and macroscopic friction developed during plastic shearing, I would like to know how the dilation angle (or contact angle) distribute in the granular layer for different PSDs and to see its relation to the volumetric strain and macroscopic friction. I hope this is clear for you. Cheers, Chien-Cheng -- 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 #697612]: Velocity distribution in paraview
Question #697612 on Yade changed: https://answers.launchpad.net/yade/+question/697612 Leonard confirmed that the question is solved: Thanks Karol Brzezinski, that solved my question. -- 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 #697612]: Velocity distribution in paraview
Question #697612 on Yade changed: https://answers.launchpad.net/yade/+question/697612 Status: Answered => Solved Leonard confirmed that the question is solved: Hi Karol Yes! Now I set the paraviw as follow and it works! Glyph Type = Arrow Scalars = linVelLen Vectors = linVelVec Thanks very much. Best regards, Leonard -- 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 #697600]: Contact (dilation) angle between particles
Question #697600 on Yade changed: https://answers.launchpad.net/yade/+question/697600 Status: Open => Needs information Jérôme Duriez requested more information: As far as I'm concerned, I would need to know what is a contact angle between particles ? -- 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 #697610]: How to get the acceleration of body
Question #697610 on Yade changed: https://answers.launchpad.net/yade/+question/697610 Status: Open => Answered Jérôme Duriez proposed the following answer: Hi, There is no such built-in function, as far as I know. Remember when applying your trick that actual acceleration will be (1+/- NewtonIntegrator.damping) F/m -- 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
