LIGGGHTS-DUMP

The dump files generated by LIGGGHTS, for the particles, can have any selection of variables. However, to be processed in Iota a minimum number of variables is required and the order is fixed. The same restriction affect the LIGGGHTS particle-particle and particle-geometry contacts files

In the particles file, the filename must have the extension ".p". The variables in the command must follow :

• id: column one

• type: column two

• x,y,z: columns three to five

• vx,vy,vz: columns nine to eleven

• radius: column eighteen

The rest of columns will be considered as user defined variables, and will be processed in that way. An example of the LIGGGHTS dump command for the particles file is:

dump Pfile all custom 400 dumpfile.p id type x y z ix iy iz vx vy vz fx fy fz &
  omegax omegay omegaz radius

The particle-particle contacts file must have the extension ".c". In this file, just the IDs of particles in contact and forces will be read:

• id: IDs of particles in contact. Columns seven to nine

• fx,fy,fz: Contact forces. Columns two ten to twelve

The rest of the columns will not be considered.

In the case of the particle-geometry contact files must have the extension ".w". The rules for such files are similar to the particle-particle contact files, with a condition on the contact point position:

• cx,cy,cz: Contact point position. Columns one to three

• id: IDs of particles in contact. Columns seven to nine

• fx,fy,fz: Contact forces. Columns ten to twelve

An example of the LIGGGHTS dump command for both contact files is:

compute cp all pair/gran/local id pos force
compute cw all wall/gran/local id pos force
dump Cfile all local 400 dumpfile.c c_cp[1] c_cp[2] c_cp[3] c_cp[4] c_cp[5] &
  c_cp[6] c_cp[7] c_cp[8] c_cp[9] c_cp[10] c_cp[11] c_cp[12]
dump Wfile all local 400 dumpfile.w c_cw[1] c_cw[2] c_cw[3] c_cw[4] c_cw[5] &
  c_cw[6] c_cw[7] c_cw[8] c_cw[9] c_cw[10] c_cw[11] c_cw[12]

In the case of the CAD wall/geometries, the only restriction is that all the meshes to be processed should be contained in a single stl file per time-step for the case of moving CAD walls/geometries. In the case of static CAD wall/geometries, it is possible to just provide a single stl file for the processing.

Example of the LIGGGHTS dump command for moving and static CAD wall/geometries files are:

• Static meshes: dump dmpstl all mesh/stl 400 dump.stl

• Moving meshes: dump dmpstl all mesh/stl 400 dump*.stl

A detailed description on how to use the LIGGGHTS DUMP files in the coarse-graining module can be found in the Input DEM data: LIGGGHTS-DUMP section.