LAMMPS WWW Site - LAMMPS Documentation - LAMMPS Mailing List Archives
Re: [lammps-users] Regarding the calculation of slip events in granular simulation
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

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


From: saikat roy <getright.roy@...24...>
Date: Thu, 3 Aug 2017 12:17:58 +0300

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

// 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);


and in the compute pair/gran/local

''else if (strcmp(arg[iarg],"forceloss") == 0) flflag = 1;

 nvalues = posflag*6 + idflag*3 + fflag*3 + fsflag*3 + flflag*3 + deltanflag + tflag*3 + hflag*dnum + aflag + hfflag;


if(flflag)
    {
        array[ipair][n++] = fl1;
        array[ipair][n++] = fl2;
        array[ipair][n++] = fl3;
    }''

These are the places where I have changed. I can succesfully dump deltan, fs1,fs2 and fs3 but not these ones. Can you please suggest where I am going wrong.

On Thu, Aug 3, 2017 at 2:01 AM, Axel Kohlmeyer <akohlmey@...24...> wrote:


On Wed, Aug 2, 2017 at 5:30 PM, saikat roy <getright.roy@...24...> wrote:
Dear all,

I am trying to calculate no of slip events in granular simulation. In order to do that I added some lines in the pair/gran model and also compute pair/gran/local. Like when ft>fn, slip=1. Now when I am trying to store this by adding a slipflag, it is giving zero. I must be doing some mistake. Can someone help me on that.

your e-mail has the same problem as your code: it is giving zero (information). 

axel.

 

thanks a lot

------------------------------------------------------------------------------
Check out the vibrant tech community on one of the world's most
engaging tech sites, Slashdot.org! http://sdm.link/slashdot
_______________________________________________
lammps-users mailing list
lammps-users@...655....net
https://lists.sourceforge.net/lists/listinfo/lammps-users




--
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.