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fix multicontact/halfspace command

Syntax:

fix ID group multicontact/halfspace geometric_prefactor gp_value 

Examples:

fix multicontact/halfspace
fix multicontact/halfspace geometric_prefactor 1.8 

Description:

Implements the multicontact model by (Brodu et al.) . This model computes a per-contact deformation for each particle based on the other contacts this particles has. A particle i with contact ij has the following new radius (when computing the contact laws with particle j):

r_i + sum_k delta_{ij->ik} 

where r_i is the default radius of particle i, sum_k is the sum over all particles in contact with i (k!=j). The delta value is given by

delta_{ij->ik} = - gamma (1 + nu) F_ik / (2 pi Y d_{ik->ij}) * [(n_ik . u_{ik->ij})(n_ij . u_{ik->ij}) + (3 - 4 nu) n_ik . n_ij - (1 - 2 nu) (n_ik + u_{ik->ij}) . n_ij) / (1 + n_ik u_{ik->ij}) ] 

where


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

No information about this fix is written to binary restart files.

fix_modify cannot be used on the parameter of this fix.

Restrictions:

Requires the use of the gran surface model multicontact

Related commands:

gran surface multicontact

Default: none

References:

(Brodu) Brodu, Dijksman, Behringer, Multiple-contact discrete-element model for simulating dense granular media, Phys. Rev. E (2015).