yade-users team mailing list archive

[Jan Stránský <question270524@xxxxxxxxxxxxxxxxxxxxx>]

Question #270524 on Yade changed:
https://answers.launchpad.net/yade/+question/270524

    Status: Open => Answered

Jan Stránský proposed the following answer:
Hello Rodrigo,
please provide a MWE [1], without it it is very difficult to guess what is
the reason of the problem
thanks
Jan

[1] https://yade-dem.org/wiki/Howtoask


2015-08-19 6:11 GMT+02:00 Rodrigo Borela <
question270524@xxxxxxxxxxxxxxxxxxxxx>:

> New question #270524 on Yade:
> https://answers.launchpad.net/yade/+question/270524
>
> Dear all,
>
> I am working on the modelling of a problem using the JCFpm contact law on
> a very dense pack (porosity is about 11%), where I have three phenomena
> being imposed simultaneously:
> 1. particle shrinkage, applied using utils.growParticles(shrinkage factor
> of the order of .9999995)
> 2. stiffening of the contacts, applied using an iterative loop on O.bodies
> (b.mat.young*=stiffeningfactor) and an iterative loop on O.interactions (
> i.phys.kn*=stiffeningfactor and i.phys.ks*=stiffeningfactor)
> (stiffeningfactor of the order of 1.0000005)
> 3. increasing tensile strength, applied also using iterative loops on
> O.bodies and O.interactions following the same procedure as in (2).
> I'm using the GlobalStiffnessTimeStepper, where the iteration interval (of
> about 500-1000 iterations) is the same as the one for when the three
> phenomena are applied.
> The problem I'm experiencing is that the time step has been decreasing at
> very large rates despite the gentle stiffening+shrinking, for example from
> 1e-8 to 1e-10 in an iteration interval. At some point, the particles
> explode or the time step becomes 'nan'.
> The work I'm doing is reproducing results from a study that employed PFC,
> and all of my coefficients and ratios are calculated according to their
> work.
> Has anyone experienced something similar and would have a suggestion to
> handle this seemingly numerical instability?
>
> Thank you in advance for your time!
>
> --
> 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.