fix particletemplate/multiplespheres command

Syntax

fix ID group-ID particletemplate/multiplespheres seed keyword values nspheres nspheresvalue ntry ntryvalue spheres values_spheres opt_keyword opt_values

  • ID, group-ID are documented in fix command

  • particletemplate/multiplespheres = style name of this fix command

  • seed = random number generator seed (integer value)

  • zero or more keyword/value pairs can be appended

  • keyword, values are documented in fix particletemplate/sphere command

  • nspheres = obligatory keyword

  • nspheresvalue = number of spheres in the template (integer value)

  • ntry = obligatory keyword

  • ntryvalue = number of tries for Monte Carlo approach

  • spheres = obligatory keyword

  • values_spheres = one out of the following options

    option 1 = file filename scale scalefactor
option 2 = x1 y1 z1 r1 x2 y2 r2... where x/y/z are sphere positions and r are the radii

  • opt_keyword = bonded or bond_type

    bonded value = one of the following options
  option 1 = yes/implicit where bonds are created based on sphere distances
  option 2 = yes/explicit nbond_pairs npairs p11 p21 p12 p22... where npairs is the number of bonded pairs and p1n/p2n are the spheres of the nth pair to be bonded
  option 3 = no
bond_type value = bond type assigned to the bonds of this particle template

Examples

fix pts1 all particletemplate/multiplespheres 41981 atom_type 1 density constant 2500 nspheres 3 ntry 10000 spheres 0.0 0.0 0.0 0.005  0.005 0.0 0.0 0.005  0.01 0.0 0.0 0.005
fix pts2 all particletemplate/multiplespheres 74163 atom_type 1 density constant 2500 nspheres 3 ntry 10000 spheres file spherefile.txt scale 1.0 bonded yes/explicit nbond_pairs 2 1 2 2 3

LIGGGHTS vs. LAMMPS Info:

This command is not available in LAMMPS.

Description

Define a multiplespheres particle template that is used as input for a fix_particledistribution_discrete command. The particle parameters (positions, radii) are either defined manually as arguments to this command or via a text file, via the keyword file. The format of this text file is

x1 y1 z1 r1
x2 y2 z2 r2
...

and the number of lines in this file has to be equal to n_spheres as defined in this command. Comments can be made in this file via the ‘#’ character. When a file is used for defining the multi-sphere template, the keyword scale must be used to define a scalefactor to scale up or down the particle positions and radii.

If the granular bond model is used, the keyword bonded can be used to define the bonds between the individual spheres of the template. If the option yes/implicit is used, bonds between spheres are created based on the skin distance. If the option yes/explicit is used, the number of bonded pairs and a list of bond partners must be specified explicitly.

The optional keyword bond_type can be used to define the type of bond that is used for this template.

Restart, fix_modify, output, run start/stop, minimize info:

Information about the random state in this fix is written to binary restart files so you can restart a simulation with the same particles being chosen for insertion. None of the fix_modify options are relevant to this fix. No global scalar or vector or per-atom quantities are stored by this fix for access by various output commands. No parameter of this fix can be used with the start/stop keywords of the run command. This fix is not invoked during energy minimization.

Restrictions

none