Implementation of a large elasto-plastic strain formalism in an industrial finite element code

Abstract: This master thesis gives a brief sum up of the implementation of a large strain formulation in an existing industrial finite element code. The logarithmic strain tensor additively decomposed in an elastic and a plastic contribution was selected as a basis of this formulation. The main advantage of this formalism is that the existing plastic resolution algorithms written in the small strain formalism can be re-used. Only a pre-processing phase (construction of the logarithmic strain tensor) and a post-processing of the stress tensor is needed. This formulation, detailed in this paper was implemented in FORTRAN and integrated to the existing code. The final implementation was then validated thanks to some benchmarks with Abaqus.