Hi everybody, Just a few comments (as usual, do not feel obliged to agree with me!)
I understand (I think) what Chiara means. This is something that bothers me a lot (mentally) and, unfortunately, it leads me to continue using my poor bits of code instead of yade (please, do not be offended by that. I love yade and I'm not being sarcastic). We have already spoken when Vaclav came to a seminar in Grenoble. I said: A parameter (physical or not) like mu (friction coefficient) has nothing to do within the bodies. This is an "inter-bodies" parameter and the bodies are rigid. The answer was: Right, but with this approach you can do what you want. For instance, if you want mu=0.4 between A-type bodies, and mu = 0.2 between A-type and B-type bodies you can do: mu_A = 0.4, mu_B = 0.0 and then mu will be defined as the mean value. I agree with that. It works fine. But I see two disadvantages: 1 - mu_A and mu_B have lost their physical meaning (if they had) 2 - I will have problem if someday (after bzr update) the mean rule if changed for a max rule by someone well-intentioned I understand that my comments are boring. Do not blame me please. The goal is to help (maybe) but not to criticize. Vincent Le 8 déc. 2010 à 15:59, Bruno Chareyre a écrit : > >> For completeness I should have included also Ks/Kn. They are all >> parameters of the interaction, however do they have a specific >> physical-basis? I am not saying that it is wrong to employ them, that is >> indeed a common assumption in a dem model. > > I'm too sure what is a "physical" parameter (for some physicists, Young > modulus and > internal friction angle are not physical parameters but engineers tricks). > > We have constitutive relations (the mathematical form) and constitutive > parameters (the > constants in there). It is logical to define constitutive parameters at the > bodies level. > Just giving a very practical reason here : I have particles of type A and B, > and I want > different values of friction for interactions A-A, A-B, and B-B (don't ask > why there > should be different, it is my constitutive assumption). How could I achieve > that if > friction was defined in the Ip functor directly? > Be it friction, kn, ks, ktw, kroll or adhesion, it makes no difference. > >> As we all know, those >> parameters are generally quantified to obtain realistic behaviour at the >> macro-scale. > > Generally, not always. You, for instance, are not doing that. > > Bruno > > > _______________________________________________ > Mailing list: https://launchpad.net/~yade-dev > Post to : [email protected] > Unsubscribe : https://launchpad.net/~yade-dev > More help : https://help.launchpad.net/ListHelp _______________________________________________ Mailing list: https://launchpad.net/~yade-dev Post to : [email protected] Unsubscribe : https://launchpad.net/~yade-dev More help : https://help.launchpad.net/ListHelp
