Three-Dimensional Modeling of Functionally Graded Multiferroic Composites

A three-dimensional (3D) finite-element-method (FEM) formulation is developed to investigate the response of functionally graded material (FGM) multiferroic composites under different types of loads. Numerical examples are carried out for the three-layered piezoelectric (PE)/piezomagnetic (PM) composite with its top and bottom layers being FGMs and the middle layer homogenous PE material. For the FGM layer, two cases of material grading along the thickness direction of the composite are considered: one is the PM material with the properties varying as an exponential function (E-FGM) and the other is the PE/PM composite material with the volume ratios varying as a power-law function (P-FGM). The effect of different material grading functions on the mechanical, electric and magnetic responses is clearly showed by both E-FGM and P-FGM grading cases, which could be useful to the future design of FGM multiferroic devices.