gran rolling_friction epsd2

Syntax

rolling_friction epsd2

LIGGGHTS vs. LAMMPS Info:

This part of pair gran and fix wall/gran is not available in LAMMPS.

Description

This model can be used as part of pair gran and fix wall/gran

The alternative elastic-plastic spring-dashpot (EPSD2) model (see Iwashita and Oda) adds an additional torque contribution. It is similar to the EPSD model, but in contrast to the original model the rolling stiffness k_r is defined as

images/pair_gran_hooke_eqEpsd5.png

where k_t is the abovementioned tangential stiffness. Furthermore, the viscous damping torque M_rd is disabled at all.

The coefficient of rolling friction (rmu) must be defined as

fix id all property/global coefficientRollingFriction peratomtypepair n_atomtypes value_11 value_12 .. value_21 value_22 .. .
    (value_ij=value for the coefficient of rolling friction between atom type i and j; n_atomtypes is the number of atom types you want to use in your simulation)

This coefficient rmu is equal to the rmu as defined in the CDT model.

Warning

You have to use atom styles beginning from 1, e.g. 1,2,3,…

(Ai) Jun Ai, Jian-Fei Chen, J. Michael Rotter, Jin Y. Ooi, Powder Technology, 206 (3), p 269-282 (2011).