2010/4/20 Bruno Chareyre <[email protected]> > On the same line : the energy dissipated by Cundall's damping in > quasi-satic conditions is negligeable. You find that the work input from > boundaries equals more or less plastic+elastic work at contacts (tests with > pfc3D, damping~0.2, frictional contacts, ~50k iterations in a triaxial > test). It corresponds with the fact that Cundall's damping looks useless in > _some_ quasi-static conditions, after Yade simulations and discussions with > Gaël, Vincent, and Vaclav. > > |Δε|*|σ| sounds straightforward, but with du and df, and non-linear > elasticty on both normal and shear, and plasticity for fun, I have no > initial guess... Computing the energy dissipated in > Law2_ScGeom_FrictPhys_basic is straightforward, for sure. > On the top of that, there is the case when plasticity==true at time "t", > and plasticity==false at time "t+dt". You have to decompose |Δε| into > plastic and elastic on one timestep. Straightforward again with the *_basic > law, but with Hertz? I have no clue yet. > Let's take Law2_ScGeom_FrictPhys_basic law. As long as we adopt the Mohr-Coulomb criterion to model friction, to me it is not so straightforward to make distinction between plastic and elastic deformation. In fact, we do not know that. In Mohr-Coulomb there is no concern about loading history. Any thoughts?
Chiara > > > > Bruno > > Václav Šmilauer a écrit : > > Put a "Real plasticWork" in the functor. Compute the energy dissipated at >>> one contact on time increment dt, and include a "plasticWork+= ..." in the >>> if(plasticityCondition) bracket of the functor. >>> Don't ask me how to define plastic work at contact with an elasto-plastic >>> Hertz-based law... ;) >>> >>> >> >> I think since the formulation is incremental, you can use |Δε|*|σ| for >> energy dissipated in plastic slip by Δε at plastic stress σ...? >> >> Generally, there is no unified function for dissipation. You could, >> though, sum kinetic energy of particles, potential energy (if there is >> some potential field), and subtract cummulative external work (boundary >> conditions). That should give you pretty good image of system energy >> evolution, including damping, plasticity and dissipation by numerical >> entropy ;-) >> >> Cheers, 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 >> >> > > > > > _______________________________________________ > 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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