A micromechanical model for the determination of nonlinear coupled electro-magneto-thermo-elastic effects on magnetoelectric composites

Magnetoelectric (ME) composites composed of piezoelectric and magnetostrictive materials have excellent energy conversion properties. In this paper, a novel micromechanical modeling framework is proposed to study the effective material properties and nonlinear electro-magneto-elastic behaviors of magnetoelectric composites under multiple physical fields. Initially, a fully coupled nonlinear electro-magneto-thermo-elastic constitutive relationship is established. Based on finite volume direct averaging micromechanics (FVDAM), the local stress, electric displacement and magnetic flux density distribution of discrete elements are obtained by constructing the generalized local stiffness matrix and assembling the global stiffness matrix. The equivalent material coefficients of the magnetoelectric composite are obtained by employing the homogenization
technique. Results of the numerical model are compared with different discrete elements and experimental data to verify the convergence and effectiveness of the developed algorithm. Moreover, effects of external prestress, ambient temperature, microscopic structure and applied magnetic field intensity on material properties such as magnetoelectric and piezomagnetic coefficients are
investigated. Finally, the influences of initial damage and constituent phase volume fraction on the equivalent material coefficient and local mechanical response are discussed. The promising results provide a solid foundation for theoretical study and useful insight into the optimal design of high performance ME composites.