Micromechanics of magnetostrictive composites

A micromechanical analysis is offered for the prediction of the effective behavior and internal field distribution of multiphase magnetostrictive composites. The analysis is based on the homogenization technique for periodic composites. The nonlinear coupled constitutive relations of the monolithic magnetostrictive have been recently established at room and elevated temperatures and verified by comparisons with experimental results. Due to the nonlinearity of these constitutive equations, the micromechanical method is based on an incremental procedure which provides the instantaneous magneto-thermo-elastic concentrations tensors that relate the local field to the externally applied loading. In addition, the analysis provides the instantaneous effective tangent tensors as well as the macroscopic constitutive equations which govern the current global behavior of the magnetostrictive composite. The present analysis provides an efficient tool for analyzing magnetostrictive composites with continuous and arbitrary inclusion phases. Results present a parametric study of the effect of applied pre-stresses, elevated temperatures and magnetostrictive phase geometry and volume fraction on a magnetostrictive/epoxy composite response that is subjected to external magnetic field. The distributions of the induced magnetostrictions in the constituents are shown in various circumstances.