> Just to say to be carefull with formula in Hentz's thesis: the idea > was to use as inputs for contact properties the Young modulus and > Poisson ratio that we want to obtain macroscopically for the granular > assembly. The "funny term" are use to compute kn and ks with respect to > these macroscopic Young modulus and Poisson ratio Yes, I know. I disregarded that funny term, it is close to 1.0 and doesn't play any role.
What struct me, though, was that we deviate from any obvious definition of contact stiffness. Its dimensionality is correct, but it is scaled by some dimensionless constant (π/2 in our case) away from the "intuitive" definition (which is the base of what Hentz uses): stiffness of cylinder with radius min(r₁,r₂) between spheres' centers, with some average Young's modulus. I say nothing if such constant is properly documented and supported by some reasoning, but for me now, even though it works, it is just garbage code. > In my opinion, the only important point is to compute kn and ks such as > scale effects are avoided, and I think it is well done in the current > formula (*) in Yade. I disagree with the premise that the only important point is to avoid scale effects. I like quantities to have physical meaning, as much as it is meaningful with discrete models; the argument (Bruno ;-) ) that discrete solution doesn't converge (and doesn't approach continuous solution) if you refine "mesh" (packing) does not justify, in my eyes, gratuitously introducing random constants to the code. Besides that, imagine Chiara reading that code (in a few days)... guess what happens? ;-) 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
