> > > > (16) is supposed to update shear force F_s (vector): > > > > F_s=F_s+K_s*ΔX_s > > > > but this is not correct, since you add ΔX_s (which is in the _current_ > > contact plane) to F_s (which is shear force from the previous step, i.e. > > in the _previous_ contact plane)!! > I don't understand the problem. F_s and ΔX_s are in the global > coordinate system, not in any contact plane.
Yes, they are in global coordinates, but, at the same time, current F_s must be always perpendicular to current n (in global coords); otherwise, we wouldn't call is F_s, right? Now, F_s from previous step is perpendicular to _previous_ n, while ΔX_s is perpendicular to _current_ n. Summing these 2 together doesn't make sense, since the sum not perpendicular to anything (neither current, nor previous n). v _______________________________________________ Mailing list: https://launchpad.net/~yade-users Post to : [email protected] Unsubscribe : https://launchpad.net/~yade-users More help : https://help.launchpad.net/ListHelp
