Syntax:
pair_style gran model hertz/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 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 for a documentation of the Hertzian model for spherical particles, and the Supplementary Note 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 youngsModulus peratomtype value_1 value_2 ... (value_i=value for Youngs Modulus of atom type i) fix id all property/global poissonsRatio peratomtype value_1 value_2 ... (value_i=value for Poisson ratio of atom type i) fix id all property/global coefficientRestitution peratomtypepair n_atomtypes value_11 value_12 .. value_21 value_22 .. . (value_ij=value for the coefficient of restitution 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 coefficientFriction peratomtypepair n_atomtypes value_11 value_12 .. value_21 value_22 .. . (value_ij=value for the (static) coefficient of friction 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
Default:
tangential_damping = 'on' limitForce = 'off'
(Herman) Agnieszka Herman, Geosci. Model Devel., submitted (2015).