Three-Dimensional Large Strain Elasto Viscoplastic Constitutive Model

Abstract

In a previous work, J. Ponthot et al., Mec Comput, XXIV:441-454 (2005), have extended a large strain elastoplastic constitutive model based on hyperelasticity and multiplicative decomposition of deformation gradient tensor, to viscous case based on a contribution of the same main author . In this way a very useful tool has been obtained, able to deal with both rate dependent and rate independent problems.
In this work a brief review of theoretical details is presented and numerical implementation of the model in a three-dimensional finite element code (SOGDE3D) is performed. The finite element code was developed for solving elastoplasticity in solids under large strains in three-dimensional space.
A Newton Raphson scheme has been used to solve the non-linear consistency condition in order to compute the viscoplastic multiplier.
An analysis of large viscoplastic deformation problems under plane strain condition are provided in order to test the proposed model. A comparison between two and three-dimensional versions of SOGDE code is achieved to validate the implementation and some results available in the literature helped to confirm the correct recovery of elastoplastic response by the viscoplastic model.