Question #136034 on Yade changed: https://answers.launchpad.net/yade/+question/136034
Václav Šmilauer proposed the following answer: > 1.a) PeriTriaxController (with dynCell=True) is not confounding statics and > dynamics : it > is purely dynamic. Eh, that is exactly what I said... It has no notion of static response, counfindg the two together (if you don't agree, it is a matter of words, I think) > 1.b) I recall there is no exact theoretical derivation of stiffness from > contact list for > "granular" materials (i.e. 3-4 interactions per element, no cohesion nor > rolling > friction); and that is the reason why I didn't use for periodic case the > static strategy > used for TT with boxes. Peri3dController is getting the response from the packing, not from formulas... >> 2. The measure of staticity depends on the formulation used (damping, >> for instance); > I don't see why unbF would depend on formulation, since it only employs > forces. I meant that choice of a suitable staticity criterion depends on what type of damping is employed. > I see no problem in that. It is not really different than > breaking a contact at iteration N, so that unbF(N+1)>unbF(N) due to ongoing > internal > reorganisations. The point was that free energy is always non-increasing (unless there is external work), that's why I though it was better. > Energy measure is consistent, but evaluating staticity and energy > conservation are two > different things. Kinetic vs. elastic energy ratio is a good measure of > staticity, but I > still have to hear what is the disadvantage of unbF, I don't see any. Above. > Considering that tracing energy is cpu-time consuming, and that there are so > many laws, > damping methods, and boundary conditions for which energy tracing is not > implemented, and > will not any time soon due to excessive complexity, I don't see energy as a > candidate for > routine staticity evaluation. Eh, alright.... I think this has become too confused a discussion to be meaningful. v. -- 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 : [email protected] Unsubscribe : https://launchpad.net/~yade-users More help : https://help.launchpad.net/ListHelp
