On 21 April 2010 15:25, Bruno Chareyre <[email protected]> wrote:
> > >> Doesn't the problem with different plasticity condition come into play >> only if you store shear force instead of strain? That would break for >> non-linear elasticity...? >> >> >> > Not sure it makes a difference. How do you define the plastic strain in > your case? I guess it uses plastic = total - elastic, with elastic = some > sort of ftmax/ks (remember... ;)). > Now, what if you cannot write elastic=ftmax/ks due to non linearity? > > Worth than that : unload the normal component with null shear velocity. It > will meet the plasticity criterion at some point (assuming purely frictional > law). Some elastic energy will be transfered to plasticity with total dUs=0. > I see this special case only now... I'll have to tackle this even for > FrictPhys_basic. > In FrictPhys we do not compute strains/stresses, so let's put everything in terms of energy. It should not be too difficult to get the plastic work (alias the energy dissipated). All we need, I think, is to know the shear displacement at current and previous time step, the shear force and the maximum shear displacement after that we slip. In formula the plastic work would read W_plastic = Fs*(us_t - us,max_t) Then we can sum up the above one among all the contacts and over the simulation time. To compute _us,max_ should I just read us,max_t = Fs_max/ks per each time step (as Fn could increase, decrease.. )? Chiara > Bruno > > > > > > v >> >> >> >> _______________________________________________ >> Mailing list: >> https://launchpad.net/~yade-users<https://launchpad.net/%7Eyade-users> >> Post to : [email protected] >> Unsubscribe : >> https://launchpad.net/~yade-users<https://launchpad.net/%7Eyade-users> >> More help : https://help.launchpad.net/ListHelp >> >> >> > > > -- > _______________ > Bruno Chareyre > Associate Professor > Grenoble INP > Lab. 3SR > BP 53 - 38041, Grenoble cedex 9 - France > Tél : 33 4 56 52 86 21 > Fax : 33 4 76 82 70 43 > ________________ > > > > _______________________________________________ > Mailing list: > https://launchpad.net/~yade-users<https://launchpad.net/%7Eyade-users> > Post to : [email protected] > Unsubscribe : > https://launchpad.net/~yade-users<https://launchpad.net/%7Eyade-users> > More help : https://help.launchpad.net/ListHelp >
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