# Copyright (c) 2017 Nikhil Admal/Jaime Marian
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# Author: Nikhil Admal
This file describes the COMSOL implementation of a three-dimensional diffuse-interface
polycyrstal plasticity developed in the paper:
Nikhil Chandra Admal, Giacomo Po, Jaime Marian.
“Diffuse-interface polycrystal plasticity: Expressing grain boundaries
as geometrically necessary dislocations.” Materials Theory, 1(1):6, 2017
The boundary-value-problem simulated is for a three-dimensional polycrystal.
See the above reference for additional details regarding the model.
This directory consists of the files
README
polycrystal.m
cdf.m
logcdf.m
expressions.m
levCiv.m
poly_cp.mph
Following are steps to be followed to run the poly_cp.mph:
1) An initial polycrystal with a log-normal distribution of grain sizes is generated using
the 'polycrystal.m' (depends on 'cdf.m' and 'logcdf.m') matlab file. The polycrystal is
outputted as three .txt files: 'orientation1.txt', 'orietation2.txt' and 'orientation3.txt'. These
files are subsequently read into COMSOL when executing poly_cp.mph.
2) Run the 'expressions.m' (depends on 'levCiv.m') matlab file which is used to generate two .txt files:
a) 'variables.txt' and b) 'pde.txt', which are used as input for variable definitions and weak
form pdes in COMSOL v5.2 file 'poly_cp.mph'.
3) Open the 'poly_cp.mph' COMSOL file. The 'poly_cp.mph' file, in its current form, has the variables
and the pdes already inputted. So, step 2 above may be skipped. Instead, if you intend to make any
changes to the model by altering the expressions.m file, then the new variables.txt and the pde.txt
files are to be included as follows:
The files variables.txt are uploaded in the tabs (of COMSOL v5.2)
Component 1 -> Definition -> variables.
The weak-form pdes in the file 'pde.txt' are pasted into the
PHYSICS tab:
Force Balance -> Weak Form PDE1
Finally, the files orientation*.txt generated in step 1 are read in the tabs
Global Definitions -> interpolation 1/2/3
4) Run the poly_cp.mph file.