A crystal plasticity based cyclic constitutive model for aluminum alloy

Abstract

A crystal plasticity based cyclic constitutive model is constructed in this paper to simulate the cyclic deformation of a rolled 5083H111 aluminum alloy. The constitutive model is built in the single crystal scale, where a modified Armstrong-Frederick nonlinear kinematic hardening rule is employed to describe the Bauschinger's effect. A simplified isotropic hardening law considering the interaction of dislocations between different slipping systems is also used. The proposed single crystal constitutive model is implemented numerically into finite element software through a user material subroutine (i.e., UMAT in ABAQUS). Then a two-dimensional polycrystalline finite element model considering the random grains' geometric shapes and crystallographic orientations is constructed. The simulated results agree quite well with correspondent experimental ones, which indicate that the proposed constitutive model is capable of predicting the cyclic deformation of the prescribed face-centered cubic (FCC) polycrystalline metal properly, including the cyclic hardening, ratchetting, and their dependence on the applied load level. The model also shows the ability to simulate the local heterogeneous deformation in a single crystal scale.