Syntax:
pair_style gran model hertz/stiffness/disk [other model_type/model_name pairs as described here ] keyword values
limitForce values = 'on' or 'off' on = ensures that the normal force is never attractive (an artefact that can occur at the end of a collision). off = standard implementation that might lead to attractive forces. tangential_damping values = 'on' or 'off' on = activates tangential damping off = no tangential damping
Description:
This pair style is part of the USER-SEAICE package; it is only enabled if LIGGGHTS was built with that package.
It requires atom_style disk and it is analogous to gran model hertz/stiffness with the difference that the formulae used to calculate the interaction forces between atoms take into account disk-shaped geometry of the atoms. See gran model hertz/stiffness for a documentation of the Hertzian model for spherical particles and the Supplementary Nore S1 to Herman (2015) for the derivation of the equations.
As in the case of other granular models, it is mandatory to use multiple fix property/global commands with this granular model:
fix id all property/global kn peratomtypepair n_atomtypes value_11 value_12 .. value_21 value_22 .. . (value_ij=value for k_n between atom type i and j; n_atomtypes is the number of atom types you want to use in your simulation) fix id all property/global kt peratomtypepair n_atomtypes value_11 value_12 .. value_21 value_22 .. . (value_ij=value for k_t between atom type i and j; n_atomtypes is the number of atom types you want to use in your simulation) fix id all property/global gamman peratomtypepair n_atomtypes value_11 value_12 .. value_21 value_22 .. . (value_ij=value for gamma_n between atom type i and j; n_atomtypes is the number of atom types you want to use in your simulation) fix id all property/global gammat peratomtypepair n_atomtypes value_11 value_12 .. value_21 value_22 .. . (value_ij=value for gamma_t between atom type i and j; n_atomtypes is the number of atom types you want to use in your simulation)
Related commands:
atom_style disk, gran model hertz/stiffness
Default:
tangential_damping = 'on' limitForce = 'off'
(Herman) Agnieszka Herman, Geosci. Model Devel., submitted (2015).