Yade

force chain between polyhedrons

Asked by Weimin Song

Dear all,

          I'm curious about the force chain output between polyhedrons in paraview.
          I find exportInteractions()[1] could output the interactions. By trying the code below, I got all the interactions.

          PyRunner(command="vtkExporter.exportInteractions('all')",iterPeriod=50)

         Now, I don't want the interaction between polyhedrons and facets, and just want the interactions between polyhedrons, could anyone give me some help how to write the code?

          Appreciate your help very much.

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Jan Stránský
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Weimin Song (wsong8) said : 		#1

[1] https://yade-dem.org/doc/yade.export.html#yade.export.VTKExporter.exportInteractions

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Jan Stránský (honzik) said : 		#2

Hi Weimin,

to visualize force chain, see [1].

to export only some interactions, use
exportInteractions(ids=intrs)
where intrs is list of (id1,id2) tuples to export. Try something like:

intrs = []
for i in O.interactions:
   b1 = O.bodies[i.id1]
   b2 = O.bodies[i.id2]
   if isisntance(b1.shape,Polyhedra) and isinstance(b2.shape,Polyhedra):
      ints.append((i.id1,i.id2))

cheers
Jan

[1]
https://github.com/yade/trunk/blob/master/doc/sphinx/user.rst#rendering-interactions-as-force-chain

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Weimin Song (wsong8) said : 		#3

Thank you, Jan.

I tried the code below, however, it doesn't work. Could you explain your approach in more detail?

def myFunction():
       intrs = []
       for i in O.interactions:
             b1 = O.bodies[i.id1]
             b2 = O.bodies[i.id2]
             if isinstance(b1.shape,Polyhedra) and isinstance(b2.shape,Polyhedra):
                 intrs.append((i.id1,i.id2))
                 vtkExporter.exportInteractions(ids=intrs)

...
O.engines=[
       ForceResetter(),
       InsertionSortCollider(...),
       InteractionLoop(...),
       NewtonIntegrator(...),
       PyRunner(command='myFunction()',iterPeriod=50),
]

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Best Jan Stránský (honzik) said : 		#4

Hi Weimin,

please always specify what does not work. "I tried the code below, however,
it doesn't work" is completely useless information :-) especially without a
complete script..

I tried the following script and it works as expected

######################################################################
from yade import plot, polyhedra_utils

O.materials.append(PolyhedraMat())
mat = O.materials[0]

O.bodies.append(wall(0,axis=2,sense=1))
O.bodies.append(wall(0,axis=1,sense=1))
O.bodies.append(wall(0,axis=0,sense=1))
O.bodies.append(wall(0.3,axis=1,sense=-1))
O.bodies.append(wall(0.3,axis=0,sense=-1))

polyhedra_utils.fillBox((0,0,0),
(0.3,0.3,0.3),mat,sizemin=[0.05,0.05,0.05],sizemax=[0.1,0.1,0.1],seed=4)

O.engines=[
   ForceResetter(),

 InsertionSortCollider([Bo1_Polyhedra_Aabb(),Bo1_Wall_Aabb(),Bo1_Facet_Aabb()]),
   InteractionLoop(
      [Ig2_Wall_Polyhedra_PolyhedraGeom(),
Ig2_Polyhedra_Polyhedra_PolyhedraGeom(),
Ig2_Facet_Polyhedra_PolyhedraGeom()],
      [Ip2_PolyhedraMat_PolyhedraMat_PolyhedraPhys()],
      [Law2_PolyhedraGeom_PolyhedraPhys_Volumetric()]
   ),
   NewtonIntegrator(damping=0.3,gravity=(0,0,-9.81)),
   PyRunner(iterPeriod=100,command="print O.iter"),
]

O.dt = 1e-3
O.run(2000,True)

from yade import export
export.VTKExporter('/tmp/exportpoly-all').exportInteractions() # ids='all'
is default
intrs = []
for i in O.interactions:
   b1 = O.bodies[i.id1]
   b2 = O.bodies[i.id2]
   if isinstance(b1.shape,Polyhedra) and isinstance(b2.shape,Polyhedra):
      intrs.append((i.id1,i.id2))
export.VTKExporter('/tmp/exportpoly-poly').exportInteractions(ids=intrs)
######################################################################

cheers
Jan
​

Revision history for this message
Weimin Song (wsong8) said : 		#5

Thanks Jan Stránský, that solved my question.