yade-users team mailing list archive

[Luc Scholtès <question693898@xxxxxxxxxxxxxxxxxxxxx>]

Question #693898 on Yade changed:
https://answers.launchpad.net/yade/+question/693898

    Status: Open => Answered

Luc Scholtès proposed the following answer:
Hi David,

1) no Hertz Mindlin contact force in JCFPM: stiffnesses are constant (linear force displacement law). The way these stiffnesses are computed is different for isOnJoint and not isOnJoint interaction though:
 
- for not isOnJoint interactions: kn is computed as in CundallStrack as a harmonic average of the particle elastic moduli such as kn=2* E1*R1*E2*R2 / (E1*R1 + E2*R2) and ks=ks = 2*E1*R1*v1*E2*R2*v2 / (E1*R1*v1 + E2*R2*v2)

- for isOnJoint interactions: kn and ks are directly assigned the values
define by the jointNormal/ShearStiffness arguments such as ki = (jki1 +
jki2)/2*contactPhysics->crossSection

2) Is it necessary to custom set every interaction ‘isOnJoint’ when
forces according to jointNormalStiffness / jointShearStiffness are
desired?

-> not sure to understand your inquiry here... I think I answered in the
previous comment but: what exactly do you want to achieve?

3) How does one achieve forces that are guided by the cross-section A
and a defined jointNormalStiffness?

-> I may not understand your questions but I think it is the case (see
previous answer). You could also define the contact stiffness based on
the surface when the interactions are set (after the first timestep of
your simulation). You would have to do that for both the material
attribute (body.mat) and the interaction attribute (interaction.phys)
through python coding (no need to modify the sources).

4) Similar to the Mindlin Physics Model, is it possible to integrate
viscous damping with a coefficient of restitution en
(Ip2_FrictMat_FrictMat_MindlinPhys(en=en))?

-> yes, that's possible but you'll need to modify the sources if you
want to combine JCFPM features with Mindlin Features (viscous damping +
joint like interactions).

I hope that's clear

Luc

-- 
You received this question notification because your team yade-users is
an answer contact for Yade.