abumpack
Fortran library with the Abaqus user material subroutines UMAT/VUMAT
... are provided. Quote this code as: A. Shterenlikht, N. A. Alexander, Levenberg-Marquardt vs Powell's dogleg method for Gurson-Tvergaard-Needleman plasticity model, Computer Methods in Applied Mechanics and Engineering 237-240:1-9 (2012). DOI: http://dx.doi.org/10.1016/j.cma.2012.04.018