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Re: [lammps-users] Regarding the calculation of slip events in granular simulation
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# Re: [lammps-users] Regarding the calculation of slip events in granular simulation

 From: Axel Kohlmeyer Date: Thu, 3 Aug 2017 08:29:23 -0400

On Thu, Aug 3, 2017 at 5:17 AM, saikat roy wrote:
Dear Axel,

Here is the detailed information. when fs>fn I am doing the calculation. The quantity of interest is slipc,lred and slideloss (part of the code where I have added some lines in pair/gran/hooke/history

​there is not much detail here either. ​what you present is without context, so it requires significant effort to recover that. there are no file names, line numbers, LAMMPS version, nothing. just some code fragments, where one has to guess what it is that you added.

// energy loss from sliding or damping
if (fs > fn) {
if (shrmag != 0.0) {
fs1 *= 0.8*fn/fs;
fs2 *= 0.8*fn/fs;
fs3 *= 0.8*fn/fs;
shear[0] = -fs1/kt;
shear[1] = -fs2/kt;
shear[2] = -fs3/kt;
fs1l = fs1/0.8;
fs2l = fs2/0.8;
fs3l = fs3/0.8;
fslmag = sqrt(fs1l*fs1l+fs2l*fs2l+fs3l*fs3l);
fsmag = sqrt(fs1*fs1 + fs2*fs2 + fs3*fs3);

lred = 0.25*sqrt(shear[0]*shear[0] + shear[1]*shear[1] +  shear[2]*shear[2]);
slideloss = 0.5*lred*(fsmag+fslmag);
slipc = fs1/fs1;
}
else fs1 = fs2 = fs3 = 0.0;
lred = 0.0*sqrt(shear[0]*shear[0] + shear[1]*shear[1] +  shear[2]*shear[2]);
slideloss = 0.0*lred*(fsmag+fslmag);
slipc = 0*fs1/fs1;

}
else
{
fs1 -= (gammat*vtr1);
fs2 -= (gammat*vtr2);
fs3 -= (gammat*vtr3);
lred = 0.0*sqrt(shear[0]*shear[0] + shear[1]*shear[1] +  shear[2]*shear[2]);
slideloss = 0.0*lred*(fsmag+fslmag);
slipc = 0*fs1/fs1;

}

fl1 = slipc;
fl2 = slideloss;
fl3 = lred;

then I am casting this into
​ ​

if(cpl && addflag) cpl->add_pair(i,j,fx,fy,fz,fs1,fs2,fs3,fl1,fl2,fl3,deltan,tor1,tor2,tor3,shear);

​i don't understand this line. where does this come from.​ there is no "cpl" class reference in any pair style in LAMMPS, and neither a method called add_pair().

and in the compute pair/gran/local

​there is no compute pair/gran/local in LAMMPS.​

are you by any chance using LIGGGHTS and not LAMMPS?
if yes, that you are posting to the wrong forum (and, of course, this would be *another* major important piece of information you have omitted).

axel.

p.s.: i would consider changing your gmail user name. you have proven it to be incorrect twice already. ;-)

--
Dr. Axel Kohlmeyer  akohlmey@...24...  http://goo.gl/1wk0
College of Science & Technology, Temple University, Philadelphia PA, USA
International Centre for Theoretical Physics, Trieste. Italy.