Question #136034 on Yade changed: https://answers.launchpad.net/yade/+question/136034
Václav Šmilauer posted a new comment: I think the criterion be derived from an exact definition of "quasi- static", which we don't have (the definition is necessarily also "quasi"). It is clear that it is a measure that will be zero for static case (no motion, or more generally no accelerations, since we are in newtonian physics); since exact zero will be only rarely achieved, one needs to set some tolerance, and therefore it should be an admimensional measure, since otherwise the threshold will have different meanings for different problem scale. The easiest adimensional params are ratios of 2 quantities with the same dimension; unbalanced force is one, but there are other possible: I am not sure if energy balance would make any difference (kinetic/elastic potential) -- it could, since physical systems conserve energy rather than forces, therefore even if they are both adimensional and one will be monotnically increasing function of the other, it can be a better measure. Never tried, though. The disadvantage of unbalanced force (or the energy ratio) is that it is not defined when there are no interactions (leading to conjuncted conditions like O.iter>1000 && utils.unabalncedForce()>0.05), which is unavoidable, seems to me. The subsequent evolution, though, as interactions get established, could be made more corresponding to expectations by multiplying e.g. by Mi/M (where Mi would be mass of particles which are in interactions, and M total mass of all particles) or something similar. (I am sorry to have no good answer, take it just as a comment...) 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
