Compute the positon of a wall

Submitted by J_Wang on Sat, 10/15/2011 - 00:43

Hi everyone,

I'm now currently doing some force controlled test by LIGGGHTS via the if then else, next and jump commands. I can control the force of a wall by the displacement of the wall in some loops. But how can know the exact displacement from its initial defined position? It is difficult to track the loops to know the displacement by calculating the time step and its velocity because in my script the wall may move up and down by conditions. Are there any commands available to output a position of a wall after the condition reached in a loop?

Thank you.

Best

J. Wang

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ckloss's picture

ckloss | Sat, 10/15/2011 - 15:56

Hi,

I guess if you controll the displacement of the wall via loops, you can also track the distance?
Also, it would be pretty easy to output that directly - fix mesh/gran stresslanalysis already outputs force and torque, it would be easy to also output the reference point p_ref of the mesh. The function you should be looking at is

230 double FixMeshGranAnalyze::compute_vector(int n)
231 {
232 //return force/torque
233 if(n<3) return force_total[n];
234 else return torque_total[n-3];
235 }

Cheers, Christoph