Plasticity regularisation, G-Cubed (2023)

Scripts: Data:

This repository contains the scripts that were used for the preparation of the manuscript: A comparison of plasticity regularisation approaches for geodynamic modelling by T. Duretz, L. Räss, R. de Borst and T. Hageman published in Geochemistry, Geophysics, Geosystems.

Installation

A specific Julia environment is provided (Project.toml file), in order to use it:

1. In Julia's REPL, switch to Pkg mode by typing ]
2. activate the project by typing: activate .
3. dowload and compile dependencies by typing: instantiate

The scripts are build using ParallelStencil. To switch from CPU to GPU computing just modify USE_GPU:

USE_GPU  = true

If your machine contains several GPUs, then you are lucky. You can select the working GPU by setting the GPU_ID:

GPU_ID   = 0

Scripts

The scripts folder contains julia scripts that can be used to reproduce the results of our study. Three different model configurations are features:

1. Single shear band formation (0_SingleShearBand folder)
2. Shear band network arising from a random cohesion field (1_RandomShearBands folder)
3. Shear banding at the crustal scale (2_CrustalScale folder)

Main parameters

These scripts were designed to study the effect of different regularisations that can be used to model frictional plastic shear banding. Each script contains a section regularisation that allows to easily switch between them. For example, this model will run with viscoplasticity and the Kelvin element viscosity is set to 2.5e20 Pa.s.

    # - regularisation
    η_vp      =  2.5e20      # Kelvin VP
    c_grad    =  0*1e13      # gradient
    coss      =  0.0         # cosserat switch
    G_coss    =  1e10        # cosserat
    l_coss    =  100.0       # cosserat

The following modification would activate gradient plasticity with a gradient parameter of 1e13 Pa.m^2:

   # - regularisation
   η_vp      =  0*2.5e20    # Kelvin VP
   c_grad    =  1e13        # gradient
   coss      =  0.0         # cosserat switch
   G_coss    =  1e10        # cosserat
   l_coss    =  100.0       # cosserat

And this one would activate Cosserat plasticity with a characteristic length of 100 m:

   # - regularisation
   η_vp      =  0*2.5e20    # Kelvin VP
   c_grad    =  0*1e13      # gradient
   coss      =  1.0         # cosserat switch
   G_coss    =  1e10        # cosserat
   l_coss    =  100.0       # cosserat

One can also combine activate viscoplasticity together with gradient or Cosserat to benefit from both spatial and temporal regularisations.