yade-users team mailing list archive

[Anton Gladky <question234450@xxxxxxxxxxxxxxxxxxxxx>]

Question #234450 on Yade changed:
https://answers.launchpad.net/yade/+question/234450

    Status: Open => Answered

Anton Gladky proposed the following answer:
Hi Raphael,

the law is written on the basis of this paper [Pournin2001]. Mass is
used there. So breaking the already implemented contact model is
highly bad idea as it will influence the results of people, which are
already using it.

Anyway, we are open to accept any contribution, so, please, provide a
patch, which you want to commit and we will try to find a suitable solution
for you.

Recently I implemented this contact law in LIGGGHTS-code and I added
"explicit"-parameter, which removes "mass-variable" if it is set. We can
probably do it and for Yade as well,so you will be able to set strength and
damping coefficient explicitly.

Cheers,

Anton

[Pournin2001]L. Pournin, Th. M. Liebling, A. Mocellin (2001),
Molecular-dynamics force models for better control of energy
dissipation in numerical simulations of dense granular media. Phys.
Rev. E (65), pages 011302. DOI 10.1103/PhysRevE.65.011302


2013/8/22 Raphaël Maurin <question234450@xxxxxxxxxxxxxxxxxxxxx>:
> New question #234450 on Yade:
> https://answers.launchpad.net/yade/+question/234450
>
> Hi all,
>
> I am using Yade in order to simulate bed load transport, i.e. granular flows driven by a turbulent fluid shear stress. For that, I am using the contact law Law2_ScGeom_ViscElPhys_Basic to take into account the dissipation occuring at contact in this dynamic situation.
>
> I modified this contact law, in order to make it be like the classical spring-dashpot law which is used in granular flow modelling, and I want to commit this changes. However this modification induces a change in the calculation of the equivalent contact stiffness and damping. In particular, I removed the weighting by the particles mass of the spring (and damping) contact parameter (it gave k = (m1k1 m2k2)/(m1k1 + m2k2)), which was surprising (not homogeneous to a stiffness/damping) and does not correspond to the classical spring-dashpot law (which is rather k = (k1 k2)/(k1 + k2))
> I did some other changes, mainly to make the ViscElMat class inherits from FrictMat, which changes the formulation (young and poisson modulus instead of normal and tangential stiffnesses) but does not affect the physics.
>
> My question is then : Is anyone using this law ? Is it a problem for anybody if I commit this changes ?
>
> Thank you,
> Best regards
>
> Raphael
>
>
> --
> You received this question notification because you are a member of
> yade-users, which is an answer contact for Yade.
>
> _______________________________________________
> Mailing list: https://launchpad.net/~yade-users
> Post to     : yade-users@xxxxxxxxxxxxxxxxxxx
> Unsubscribe : https://launchpad.net/~yade-users
> More help   : https://help.launchpad.net/ListHelp

-- 
You received this question notification because you are a member of
yade-users, which is an answer contact for Yade.