tangential model history/time_dependent

Purpose

This tangential model is equivalent to the tangential model history but can vary its coefficient of friction with time.

Syntax

tangential history/time_dependent [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)

heating_tangential_history values = 'on' or 'off'
  on = model contributes to surface heating in the frame of enable_surface_heating
  off = model does not contributes to surface heating
torsion values = 'on' or 'off'
  on = model calculates friction based on torsion
  off = model ignores rotation around the contact normal

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

coefficientFriction ( $\mu_0$ ): The coefficient of friction acting between two materials [ $\cdot$ ]
coefficientRestitution ( $e$ ): The coefficient of restitution of two materials [ $\cdot$ ]
coefficientFrictionModifier ( $f_\mu$ ): The coefficient of friction modifier (can be a file) [ $\cdot$ ]

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 to the standard model is that the coefficient of friction depends on time $t$ via

$\mu = \mu_0 f_\mu(t)$

Note, as coefficientFrictionModifier is an interaction property each interaction can have different inputs dependent on the associated material properties.

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

heating_tangential_history = ‘off’, torsion = ‘off’