On 21 April 2010 16:18, chiara modenese <[email protected]> wrote:
> > > 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 > > of course If us,max_t > us_t > W_plastic = Fs*(us_t - us,max_t) > otherwise W_plastic = 0 > > 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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