tangential model no_history

Purpose

A simplified tangential model with a damping term only. Should only be used for initialization purposes.

Syntax

tangential no_history [other model_type/model_name pairs as described here ] keyword values

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

disableTangentialWhenBonded values = 'on' or 'off'
  on = if the cohesion bond model is used, then the tangential force is only added if the two particles are not bonded
  of = the normal force is always added if two particles overlap

computeDissipatedEnergy values = 'on' or 'off'
  on = the tangential model saves the dissipated energy for each contact for the
  use in fix calculate/dissipated_energy
  of = no values are saved

Associated material properties

Material properties

youngsModulus ( $Y$ ): The Youngs Modulus of a material, i.e. its stiffness [pressure]
poissonsRatio ( $\nu$ ): The Poisson’s ratio, i.e. the ratio of transverse to axial strain [ $\cdot$ ]

Material interaction properties

coefficientRestitution ( $e$ ): The coefficient of restitution of two materials [ $\cdot$ ]
coefficientFriction ( $\mu$ ): The coefficient of friction acting between two materials [ $\cdot$ ]

Description

This model can be used in the tangential argument of both particle_contact_model and wall_contact_model.

This model calculates the tangential force between two particles in contact as done in the tangential model history.

The difference in this model is that the spring constant $k_t = 0$ . Thus, the force depends only on the relative velocity and has only a damping contribution. Because of this, this model should not be used in a simulation where forces are measured. Instead it can be useful for initialization of a packing as it is slightly faster than the history model.

When the cohesion model bond is used the disableTangentialWhenBonded keyword can be used. If this parameter is set to ‘on’ then the tangential model will only compute its contribution if the two neighboring particles do not have an active bond.

Coarse-graining information:

Using coarsegraining in combination with this command should lead to statistically equivalent dynamics in the system.