This document summarizes the main ideas of the finite element method (FEM) theory and constitutive relations as implemented in the PHIMATS code (https: //github. com/ahcomat/PHIMATS. gitGitHub Repository). Rather than detailing the derivations or specific models, this document focuses on the key mathematical foundations and numerical strategies used within the implementation. For in-depth theoretical discussions, the reader is encouraged to consult the references. For citing this document, please use. . . Hands-on examples can be found in CaseStudies directory on the GitHub repository. .
Abdelrahman Hussein (Sat,) studied this question.