SlidingDrivenStrainRate

Source: models/solid_mechanics/traction_separation_law/SlidingDrivenStrainRate.py

Local stand-in for the bulk strain rate that drives nucleation,

\[ \dot{\varepsilon} = \frac{\left| \dot{[\![u]\!]}_t^v \right|}{d}, \]

with \(d\) a characteristic grain or grain boundary length scale.

The bulk strain rate is the only non-local quantity in the original Sham-Needleman model. Assuming nucleation is driven by sliding stress concentrations replaces it with this purely local expression, which is what makes the simplified model usable as an interface law without a coupling back to the surrounding continuum.

This leaf is optional by construction: the nucleation law consumes strain_rate as an ordinary input, so an input file may instead supply the true bulk rate (for example through a ScalarInputParameter) and leave this model out of the composition entirely.

Inputs

viscous_sliding_rate — input · Scalar · required

Rate of the viscous part of the sliding jump

Outputs

strain_rate — output · Scalar · required

Effective strain rate driving cavity nucleation

Parameters

length_scale — parameter · Scalar · required

Characteristic grain or grain boundary length scale