cohesion model sjkr/selective

Purpose

Modelling material cohesion using a modified version of the simplified Johnson-Kendall-Roberts (SJKR) cohesion model.

Syntax

cohesion sjkr/selective [other model_type/model_name pairs as described here ] settings keyword values

zero or one keyword/value pairs may be appended to the end (after all models are specified)

tangential_reduce values = 'on' or 'off'
  on = tangential model does not see normal force computed by this model
  off = tangential model does see normal force computed by this model

Associated material properties

Material interaction properties

cohesionEnergyDensity ( $k$ ): cohesion energy density between the two materials [energy/length^3]

Description

This model adds a “selective” cohesion force, where “selective” means that cohesive forces are only applied to particles which overlap before a neighbor list build detects that they are close to each other. Typically, that only happens if particles are inserted with an initial overlap, e.g. by using a fix particletemplate/multiplespheres command where the spheres already initially overlap. This can be used to model cohesively bonded agglomerations of particles, which can break apart once the forces on the agglomerate become too high.

Warning

An initial overlap can also be caused by a so-called “dangerous build”, a special situation in neighbor list builds due to errors in the set-up, which is described here: Section_start

The cohesive force itself is identical to the description in cohesion sjkr

Restrictions

See cohesion sjkr

Coarse-graining information:

Using coarsegraining in combination with this command might lead to different dynamics or system state and thus to inconsistencies. However, the influence of this model on the global dynamics or system state might be small so in some cases the results may be valid. This has to be reviewed by a specialist on a case-by-case basis.

Default

See cohesion sjkr