pair/gran/hooke and wall/gran/hooke does not work correctly. For example, the source "pair_gran_hooke.cpp" contains lines number 197-206 with the code:
// force normalization
fn = xmu * fabs(ccel*r);
fs = gammat*vrel;
if (vrel != 0.0) ft = MIN(fn,fs) / vrel; ======== ??? ========
else ft = 0.0;
// tangential force due to tangential velocity damping
fs1 = -ft*vtr1;
fs2 = -ft*vtr2;
fs3 = -ft*vtr3;
If gammat is equal zero, then friction between the particles will be always equal to zero.
ckloss | Tue, 11/26/2013 - 10:03
Hi sirop,
Hi sirop,
I am not sure if I understand where you think something is missing
Usually, in DEM (for spring-dash-pot models) the tangential force consists of
a spring and a dashpot force. Plain Hooke (without history) misses the spring part
for the tangential force, as this requires contact/shear history. What remains
is the dashpot part
Best wishes
Christoph
Cheers
Christoph