CO-ROTATIONAL FORMULATION AND IMPLEMENTATION OF AN INVARIANT-BASED MODEL FOR GEOMETRICALLY NONLINEAR ANALYSES OF COMPOSITES

Abstract

A co-rotational formulation and implementation of an invariant-based anisotropic plasticity model is presented for
geometrically nonlinear analyses of Fiber Reinforced Polymer (FRP) composites. The anisotropic constitutive
equations are formulated in the format of isotropic tensors functions. The model assumes an anisotropic pressure
dependent yield function, and in addition to this, a non-associated plastic potential in order to model more realistic
plastic deformations in FRP. The formulation is then cast in the co-rotational framework and implemented in the
commercial finite element software Abaqus/Standard via the means of the user-defined capability UMAT. The finite
deformation kinematics within the co-rotational frame are described and the important aspects regarding the numerical
treatment and implementation are discussed. The performance of the model is assessed via a set of numerical
simulations, which demonstrate its applicability and robustness.