Third M.I.T. Conference on Computational Fluid and Solid Mechanics June 14–17, 2005  

An efficient numerical modelling of anisotropic structural behaviour in large strain elastoplasticity

Igor Karšaja,*, Carlo Sansourb, Jurica Sorića
aFaculty of Mechanical Engineering and Naval Architecture, University of Zagreb, I. Lučića 5, HR-1000 Zagreb, Croatia bThe University of Adelaide, Department of Mechanical Engineering, SA 5005, Australia

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The paper deals with aspects of anisotropic elastoplastic analysis at finite strain. The material model is based on the multiplicative decomposition of the deformation gradient. An anisotropic elastic constitutive law, described in invariant setting by the use of structural tensors, is presented. An anisotropic Hill-type yield criterion, described by an Eshelbylike stress tensor and further structural tensors, is developed. It considers nonlinear isotropic hardening as well. Explicit results for the specific case of orthotropic anisotropy are given. An accurate and trivial wise objective integration algorithm employing the exponential map is given. The numerical example demonstrates the influence of anisotropy on the elastoplastic deformation process as well as the robustness and accuracy of the proposed formulation.

Keywords:  Elastic orthotropy; Orthotropic yield function; Multiplicative inelasticity; Finite strain; Isotropic hardening; Exponential map

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