Bonding particles with JCFpm yields unexpected forces
Dear Yade community,
being new to yade I lack some basic understanding about the constitutitve law ‘Law2_ScGeom_
Problem Formulation:
Question 635871 [1] states that the JCFpm law is an implementation of Potyondy & Cundalls ‘A bonded particle model for rock’ [3]. I would therefore expect a Hertz Mindlin contact force [2. eq: 33-36], updated by a force proportional to a set bond normal (and shear) stiffness and the cross section A [3. eq: 14], as proposed by Potyondy & Cundall.
The following minimal test example with two spheres, each customly set ‘onJoint=True’ and the interaction set ‘isOnJoint=True’, shows that the normal force is proportional to: 2*young*
Minimal example:
mat=JCFpmMat(
#Creating Spheres
s1 = utils.sphere(
s2 = utils.sphere(
s2.state.vel = (0,0,-1.)
O.bodies.
O.engines=[
ForceResetter(),
InsertionSor
InteractionLoop(
),
NewtonIntegr
]
O.dt = .05*utils.
O.step()
bo1s.aabbEnlarg
ig2ss.interacti
#Set sphere state and interactions manually 'onJoint'
for i in O.interactions:
O.bodies[
O.bodies[
O.bodies[
i.phys.isOnJoint = True
#Check if force is related to jointNormalStif
O.run(10,True)
i = O.interactions[0,1]
print('isOnJoint = ',i.phys.isOnJoint)
print('
Output:
>>> isOnJoint = ', True, normalStifness=, 30000000000.0, normalForce=, Vector3(
Questions:
1) Is it necessary to custom set every interaction ‘isOnJoint’ when forces according to jointNormalStif
2) How does one achieve forces that are guided by the cross-section A and a defined jointNormalStif
3) Similar to the Mindlin Physics Model, is it possible to integrate viscous damping with a coefficient of restitution en
(Ip2_
[1]: [https:/
[2]: [https:/
[3]: [https:/
Question information
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- English Edit question
- Status:
- Solved
- For:
- Yade Edit question
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- Solved by:
- Luc Scholtès
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