> One remark : implementing this for arbitrary deformation needs 9 > "goals", compared to 9 components of F or stressTensor. A typical > example : compression along z axis with imposed dεzz/dt while σxz is > kept constant (i.e. velgGradxz will be assigned by the engine to keep > sxz constant, and velGradzz will be defined to make log(Fzz) reach goalzz ). I think just 6 goals will do, since shear stresses will be (in equilibirum) symmetric.
> One question : how can it be adapted to isotropic compression, where > goal is (sx+sy+sz)/3 and the constraint is ex=ey=ez? Too many constraints, the system is overdetermined. You would just need ex=ey && ex=ez && sx=sig/3. Plus one condition for strain rate, which is the fourth, time DOF. I actually wanted to have one big system (matrix) and then eliminate columns corresponding to given goals (which would move to RHS) etc, but that will need incremental formulation, and a few thoughts how to handle absolute goals in that case... > This is why I implemented cell inertia. Did you fix this or it was not > really a problem? I didn't fix it, but inertia has nothing to do (?) with material stiffness? It is just "dynamic" stiffness. > If you apply a (non-isotropic) scaling on normalized Hsize vectors, it > will "shear" them (the angles between axis will change), right? Yes, unless I misunderstand what you mean ;-) v _______________________________________________ Mailing list: https://launchpad.net/~yade-dev Post to : [email protected] Unsubscribe : https://launchpad.net/~yade-dev More help : https://help.launchpad.net/ListHelp
