I am in a sticky situation.
I have been given a UMAT which describes a material in abaqus. I am fairly new to it, but the problem is that the UMAT has been written by at least 4 people, over a couple of years. It does not have much of commenting neither is there any knowledge base.
I want to know the best method to understand the UMAT by myself (ex : Can I debug the UMAT at each stage and then understand the flow, oare there any other techniques?). The abaqus Manual is good, but only with the definitions.
Thank you !
I would suggest to take two-steps:
1) Write a VERY SIMPLE umat on your own. e.g. a linear elastic material, just to understand how it works. Abaqus documentation provides example code. DON'T use it. Have the help open, but type the code yourself! For each variable you type, ask yourself what it is and why you need it.
The goal of this is to UNDERSTAND umat, not just read the instructions.
2) Once you have "mastered" umat coding, proceed to your Group's umat. Again, write it yourself from scratch. e.g. print it and type the code again (like a "copy/paste by hand"). At each step ask yourself about the variables. Start from the main routine, and as the program flows, you will eventually understand why the various subroutines are needed and what they do and how they do it (I assume that umat is calling many auxiliary subroutines).
I know this manual copy/paste may seem like time-waste, but it will help you understand the thinking of the developers before you.
Good Luck
Look at this:
http://mashayekhi.iut.ac.ir/sites/mashayekhi.iut.ac.ir/files/u32/presentation1516.pdf
Look at this:
http://imechanica.org/files/Writing%20a%20UMAT.pdf
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