Syntax:
rolling_friction epsd2
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
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.
IMPORTANT NOTE: 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).