UMAT-to-VUMAT Conversion Code for Abaqus

Published: 19 January 2026| Version 1 | DOI: 10.17632/6g35cy43jk.1
Contributor:
Zhenyu Liu

Description

This repository provides a UMAT-to-VUMAT conversion code that assists in migrating user material subroutines from Abaqus/Standard (UMAT) to Abaqus/Explicit (VUMAT). The code automates key interface and data-structure translations (e.g., stress/strain component ordering and state-variable handling) and generates a VUMAT-ready template. The conversion workflow is intended to reduce manual editing effort and common implementation errors when transferring constitutive models between implicit and explicit solvers. The package includes the conversion scripts, parallel Fortran 90/95 (free-form) and Fortran 77 (fixed-form) source files, and brief usage notes. The release is distributed under GNU GPL v2.0; portions of this release are derived from upstream GPLv2 code by Bienen et al. (2014); the original source is available at https://soilmodels.com/download/vumat_umatinterface-zip/ Users should verify the converted VUMAT against element-level benchmarks and problem-specific tests before production analyses.

Files

Steps to reproduce

Please read the README carefully before use. Not applicable for full reproduction of paper results; this deposit provides a conversion template and usage notes for converting a UMAT subroutine into a VUMAT interface in finite element package Abaqus. You will need to adapt both your UMAT source code and (if necessary) the provided conversion template to enable direct porting of the UMAT subroutine into the VUMAT interface.

Institutions

  • The University of Melbourne
  • University of Toronto

Categories

Software, Geotechnical Engineering, Numerical Algorithm, Source Coding, Finite Element Method, Constitutive Modeling

Licence