Re: [Yade-users] [Question #293445]: Polyhedra Elements, Infinite Loop.

[MikeZhao]

Question #293445 on Yade changed:
https://answers.launchpad.net/yade/+question/293445

MikeZhao gave more information on the question:
The new engine is as following:
O.engines = [
ForceResetter(),
InsertionSortCollider([Bo1_Polyhedra_Aabb()]),
InteractionLoop(
[Ig2_Polyhedra_Polyhedra_PolyhedraGeom()],
[Ip2_PolyhedraMat_PolyhedraMat_PolyhedraPhys()],
[Law2_PolyhedraGeom_PolyhedraPhys_Volumetric()]
),
NewtonIntegrator(damping=0),
]

According to my test, this bug happens during Yade.O.step().

I have added several cout codes at the begining and the end of several
places. It turns out that this bug doesn't locate in
Ig2_Polyhedra_Polyhedra_PolyhedraGeom::go,
Ip2_PolyhedraMat_PolyhedraMat_PolyhedraPhys::go or
Law2_PolyhedraGeom_PolyhedraPhys_Volumetric::go.

Could anybody tell me where this bug possibly locate? Thanks a lot.

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Re: [Yade-users] [Question #293445]: Polyhedra Elements, Infinite Loop.

[MikeZhao]

Question #293445 on Yade changed:
https://answers.launchpad.net/yade/+question/293445

Status: Answered => Open

MikeZhao is still having a problem:
I have updated yade, using trunk-master. However, this problem still
exists:

The speed of my calculation is about 5 steps per second, however when it
comes to a certain step, it will hold there while the usage of CPU
remains 100%. I am pretty sure that this program encountered an infinite
loop when yade.O.step() is called..

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[Yade-users] [Question #293471]: Circular RandomDensePack with CpmMat

[mohsen]

New question #293471 on Yade:
https://answers.launchpad.net/yade/+question/293471

In the name of god
Hello all
I want to simulate a gravity deposition. The particles are generated in a 
circular predicate. If FrictMat is used, there is no problem and the particles 
flow freely on the horizontal wall; But in the case of CpmMat, it seems that 
the bonds between particles is made.
With regarding to this point that i have setted intRadius = 1 and there is no 
initial overlap, why bonds between particles are made?


from yade import pack

mat=CpmMat(young=1e9,neverDamage=True,epsCrackOnset=1e-2)  
O.materials.append(mat)

###generating circular predicate and filling with spheres
pred=pack.inCylinder(centerBottom=(0.5,0.5,0),centerTop=(0.5,0.5,1),radius=.25)
spheres=pack.randomDensePack(pred,spheresInCell=500,radius=.55e-1)
O.bodies.append(spheres)

O.bodies.append(wall(-0.1,axis=2))

intRadius = 1

O.engines = [
ForceResetter(),
InsertionSortCollider([Bo1_Sphere_Aabb(aabbEnlargeFactor=intRadius,label='is2aabb'),Bo1_Wall_Aabb()]),
InteractionLoop(
[Ig2_Sphere_Sphere_ScGeom(interactionDetectionFactor=intRadius,label='ss2d3dg'),Ig2_Wall_Sphere_ScGeom()],
[Ip2_CpmMat_CpmMat_CpmPhys()],
[Law2_ScGeom_CpmPhys_Cpm()]
),
NewtonIntegrator(gravity=(0,0,-10),damping=0.5)
]
O.dt = 0
O.step()
is2aabb.aabbEnlargeFactor = 1.
ss2d3dg.interactionDetectionFactor = 1.

O.dt=.5*PWaveTimeStep()


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Re: [Yade-users] [Question #293295]: Want to connect all the particles in an aggregate using cohesive bond

[whr]

Question #293295 on Yade changed:
https://answers.launchpad.net/yade/+question/293295

Status: Open => Answered

whr proposed the following answer:
Hi varun,

I did not go through your script. But from your description in  #3, this may be 
due to the value of cohesion. 
The value of shearCohesion/normalCohesion within the existing interactions will 
not change if you just change the value. You need another setCohesionNow to 
reset it. 
Since the very high cohesion value result in the correct number of cohesive 
interactions, you may want to find a proper value that make the initial 
interaction number correct and these bonds could be broken in the following 
process.

Cheers,
Huanran

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[Yade-users] [Question #293468]: Force controller

[ntthangvn]

New question #293468 on Yade:
https://answers.launchpad.net/yade/+question/293468

hi every YADE users,

My name is Thang, a PhD student in Monash Uni.  I have tried to model a 
cantiliver beam support to a load P=1Mpa
Normally, I use Displacement controller by applying velocity on one particle or 
addtional facets, but I dont know how to use force controller by applying 
additional load on this beam. Could anyone help me to solve the problem? 

Thank you so much for your kind help!


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Re: [Yade-users] [Question #293468]: Force controller

[ntthangvn]

Question #293468 on Yade changed:
https://answers.launchpad.net/yade/+question/293468

Description changed to:
hi every YADE users,

My name is Thang, a PhD student in Monash Uni.  I have tried to model a 
cantiliver beam support to a load P=1kN
Normally, I use Displacement controller by applying velocity on one particle or 
addtional facets, but I dont know how to use force controller by applying 
additional load on this beam. Could anyone help me to solve the problem? 

Thank you so much for your kind help!

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Re: [Yade-users] [Question #293295]: Want to connect all the particles in an aggregate using cohesive bond

[VG]

Question #293295 on Yade changed:
https://answers.launchpad.net/yade/+question/293295

Status: Solved => Open

VG is still having a problem:
Thanks Jan!
 Thanks to Bruno, I actually found part of the solution here: 
https://answers.launchpad.net/yade/+question/256364
 However, there is something additional described below which I am trying to 
find an answer for.

There are two things which I am doing now in addition to the above script:
 1. Using a value of 1.1 for aabbEnlargeFactor and interactionDetectionFactor 
for collision and interaction respectively.
 2. Using very high normal and shear cohesion values in the first iteration: 
~1e20 and then resetting these values to the original values.

This results in the correct number of cohesive interactions in each
aggregate. However, with the application of the load, these cohesive
bonds don't seem to break anymore.

I am using the commands in the following sequence:

-- In the initial definition of material properties for sample material, set 
very high values of cohesion ~1e20
-- Run one iteration using O.step()
-- Reset the value of cohesion parameters by:
   sample_material.normalCohesion = 1e8*1.2
   sample_material.shearCohesion = 0.4*1e8*1.2
-- O.run()

I also checked the value of sample_material.normalCohesion from command
line interface, and it shows the correct value.

Is there a problem in the sequence of commands ? I think I am pretty close to 
finding a solution but not there yet. 
May be when I am setting very high values of normal and shear cohesion 
initially, some parameters are calculated internally and those need to be reset 
as well after the first iteration ?

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Re: [Yade-users] [Question #293295]: Want to connect all the particles in an aggregate using cohesive bond

[VG]

Question #293295 on Yade changed:
https://answers.launchpad.net/yade/+question/293295

Status: Answered => Solved

VG confirmed that the question is solved:
Thanks Jan! 
Thanks to Bruno, I actually found part of the solution here: 
https://answers.launchpad.net/yade/+question/256364
However, there is something additional described below which I am trying to 
find an answer for.

There are two things which I am doing now in addition to the above script: 
1. Using a value of 1.1 for aabbEnlargeFactor and interactionDetectionFactor 
for collision and interaction respectively. 
2. Using very high normal and shear cohesion values in the first iteration: 
~1e20 and then resetting these values to the original values.

This results in the correct number of cohesive interactions in each
aggregate. However, with the application of the load, these cohesive
bonds don't seem to break anymore.

I am using the commands in the following sequence:

-- In the initial definition of material properties for sample material, set 
very high values of cohesion ~1e20
-- Run one iteration by O.step()
-- Reset the value of cohesion parameters by: 
sample_material.normalCohesion = 1e8*1.2
sample_material.shearCohesion = 0.4*1e8*1.2

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Re: [Yade-users] [Question #291326]: Packing and predicate dimension

[Luis Barbosa]

Question #291326 on Yade changed:
https://answers.launchpad.net/yade/+question/291326

Status: Answered => Solved

Luis Barbosa confirmed that the question is solved:
Thanks Jérôme Duriez, that solved my question.

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Re: [Yade-users] [Question #293295]: Want to connect all the particles in an aggregate using cohesive bond

[Jan Stránský]

Question #293295 on Yade changed:
https://answers.launchpad.net/yade/+question/293295

Status: Open => Answered

Jan Stránský proposed the following answer:
Hi Varun,
I see the main problem in how to correctly create cohesive interactions
between particles with CohFrictMat. Unfortunately, I am not familiar with
this model. You have to wait for somebody experienced with the model :-) or
you can search CohFrictMat in previous questions [1]..
cheers
Jan

[1] https://answers.launchpad.net/yade


2016-05-04 23:42 GMT+02:00 VG :

> New question #293295 on Yade:
> https://answers.launchpad.net/yade/+question/293295
>
> Hello everyone,
>
> Here is a description of the problem I am trying to solve:
>
> -- I have a granular sample with spherical particles of diameters D1, D2,
> D3 etc. All of such big particles (lets call them agglomerates) are
> composed of smaller particles of diameter 'd', since d is the smallest
> particle size of interest.
>
> -- Initially, within each big spherical particle, all the smaller
> particles should be densely packed and connected with cohesive bonds
> (CohFrictMat). As the loading is applied, the initially defined cohesive
> bonds within each big sphere will break progressively leading to smaller
> fragments.
>
> Now, the problem I am facing: Initially, within a single big sphere
> itself, sometimes there are particles which are shown not to have any
> cohesive interaction, leaving the small individual particle free to fly.
> How can I alleviate this problem ?
>
> This is a follow-up question to
> https://answers.launchpad.net/yade/+question/292846
>
> Here is the script:
>
>
> from yade import pack
>
>
> #
> # Set up run
>
> #
> run_name="PeriodicCohesive_MWE"
> data_root_dir="."
>
>
>
>
> #
> # Materials
>
> #
> plate_material=FrictMat(
> young=200e9
> ,poisson=0.3
> ,density=8000.
> ,frictionAngle=radians(30)
> ,label='plate_mat')
>
> O.materials.append(plate_material)
>
>
> sample_material=CohFrictMat(
> young=4e9
> ,poisson=0.25
> ,density=1400
> ,frictionAngle=radians(30)
> ,normalCohesion=1e8*1.2
> ,shearCohesion=.4e8*1.2
> ,momentRotationLaw=True
> ,label='sample_mat')
> O.materials.append(sample_material)
>
>
>
>
> #
> # Component dimensions and operating condition
>
> #
> # Granular material dimension
> sample_diameter=2e-4
> #sample_diameter=126e-6
> sample_radius=sample_diameter/2.0
> # Sub-particle dimension
> particle_diameter=74e-6
> particle_radius=particle_diameter/2.
>
>
> #
> # grinding plate dimension
>
> #
>
> rotvel=2./3.*pi*(1.5+0.5)*.254
>
>
> #
> # Periodic Geometry
>
> #
>
>
> # Set up periodic boundary conditions
> O.periodic=True
> xExt=4*sample_diameter
> yExt=3.*sample_diameter*2 #to block the periodicity in y direction
> zExt=xExt
> xLim=xExt
> yLim=yExt/4
> zLim=zExt
> O.cell.hSize=Matrix3(
> xExt, 0, 0,
> 0, yExt, 0,
> 0, 0, zExt)
>
>
> length=xExt
> height=yExt
> width=zExt
>
> # Top and bottom plate thickness
> thickness=0.1*height
>
>
>
>
>
> bottomBoxes = []
> for ix in (0,1,2):
> for iz in (0,1,2):
> bottomBoxes.append(box( # create 3x3 boxes with 1/3 cell
> size
> center=(xExt/6.*(1+2*ix),yLim -
> thickness/2.0,zExt/6.*(1+2*iz))
> ,extents=(xExt/6.,thickness/2.0,zExt/6.)
> ,wire=False
> ,material='plate_mat'
> ))
>
> bottom_id,bottom_ids = O.bodies.appendClumped(bottomBoxes) # bottom_id is
> the clump id,
>
>
> O.bodies[bottom_id].state.blockedDOFs='xyzXYZ'
>
>
>
>
> #
> # Particle Packing
>
> #
>
> min_corner= (0,yLim,0)
> max_corner= (xLim, yExt-yLim, zLim)
>
> sp=pack.SpherePack()
> sp.makeCloud( min_corner,max_corner, rMean=sample_radius, periodic=False,
> seed=1)
>
> print "Generated ",len(sp)," aggregates"
>
> ###
> # Sample
> ###
> for s in sp:
> 

Re: [Yade-users] [Question #293445]: Polyhedra Elements, Infinite Loop.

[Anton Gladky]

Question #293445 on Yade changed:
https://answers.launchpad.net/yade/+question/293445

Anton Gladky proposed the following answer:
You can try yadedaily which is updating permanently now
for most supported Debian-based distributions.

Best regards

Anton

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Re: [Yade-users] [Question #293445]: Polyhedra Elements, Infinite Loop.

[Jan Stránský]

Question #293445 on Yade changed:
https://answers.launchpad.net/yade/+question/293445

Status: Open => Answered

Jan Stránský proposed the following answer:
Hi Mike,
according to PolyhedraVolumetricLaw (which was renamed to
Law2_PolyhedraGeom_PolyhedraPhys_Volumetric), it seems you have an older
version of Yade. Since then, there were some changes in polyhedra code. Is
it possible for you to try the script with some newer version?
cheers
Jan


2016-05-08 8:57 GMT+02:00 MikeZhao :

> New question #293445 on Yade:
> https://answers.launchpad.net/yade/+question/293445
>
> I have been working on building finite-discrete element model to simulate
> fracture generation, and polyhedra elements in yade are used for DEM.
>
> After several steps, it seems that an infinite loop occurs when
> yade.O.step() is called. I want to trace back to the source of this bug,
> but it seems O.step() has called several functions in boost library, and it
> is hard for me to understand what codes in Yade are involved for O.step().
>
> Could you please give me some advice on locating this bug? It will be very
> helpful if someone can tell my what codes in Yade are called for O.step().
>
> By the way, the engine I used is as following:
> O.engines = [
> ForceResetter(),
> InsertionSortCollider([Bo1_Polyhedra_Aabb()]),
> InteractionLoop(
> [Ig2_Polyhedra_Polyhedra_PolyhedraGeom()],
> [Ip2_PolyhedraMat_PolyhedraMat_PolyhedraPhys()],
> [PolyhedraVolumetricLaw()]
> ),
> NewtonIntegrator(damping=0),
> ]
>
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>

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[Yade-users] [Question #293445]: Polyhedra Elements, Infinite Loop.

[MikeZhao]

New question #293445 on Yade:
https://answers.launchpad.net/yade/+question/293445

I have been working on building finite-discrete element model to simulate 
fracture generation, and polyhedra elements in yade are used for DEM. 

After several steps, it seems that an infinite loop occurs when yade.O.step() 
is called. I want to trace back to the source of this bug, but it seems 
O.step() has called several functions in boost library, and it is hard for me 
to understand what codes in Yade are involved for O.step().

Could you please give me some advice on locating this bug? It will be very 
helpful if someone can tell my what codes in Yade are called for O.step().

By the way, the engine I used is as following:
O.engines = [
ForceResetter(),
InsertionSortCollider([Bo1_Polyhedra_Aabb()]),
InteractionLoop(
[Ig2_Polyhedra_Polyhedra_PolyhedraGeom()],
[Ip2_PolyhedraMat_PolyhedraMat_PolyhedraPhys()],
[PolyhedraVolumetricLaw()]
),
NewtonIntegrator(damping=0),
]

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Re: [Yade-users] [Question #290946]: Several Errors occured while using tetraPoly elements

[MikeZhao]

Question #290946 on Yade changed:
https://answers.launchpad.net/yade/+question/290946

Status: Answered => Solved

MikeZhao confirmed that the question is solved:
I have located the position of this bug recently, it seems that
segmentation fault bug is caused by CGAL::convex_hull_3(), and it is a
known bug. Adjust "DISTANCE_LIMIT" larger according to the size of the
mesh and adjust "MERGE_PLANES_LIMIT" larger might reduce this problem.

Sorry for my late reply: I have been working on establishing fem-dem
model, and this bug is hard to reproduce, so I have tried to locate and
solve it myself.

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