Multiscale finite element simulations of piezoelectric materials based on two- and three-dimensional electron backscatter diffraction–measured microstructures

This article presents a computational procedure for evaluating effective homogenized material properties of polycrystalline piezoelectric materials and constructing two- and three-dimensional realistic microstructure models based on electron backscatter diffraction crystal orientation measurement. Microstructural features of a polycrystalline piezoelectric material, barium titanate, were investigated through electron backscatter diffraction measurements using an amorphous osmium coating to prevent charging. Realistic crystal orientations obtained from the electron backscatter diffraction measurements were introduced into multiscale finite element simulations based on homogenization theory to reveal the relationship between the macrostructure and the microstructure. First, a two-dimensional microstructural model was constructed, and the effect of the sampling area of the electron backscatter diffraction–measured crystal orientations was analyzed. We discuss the representative volume element determined from two points of view: the macroscopic homogenized material properties and the microscopic localized material behavior in response to external loads. Second, the surface of specimen was ground and polished at regular intervals and was measured by electron backscatter diffraction iteratively. Then a three-dimensional microstructural model was constructed by stacking in-plane crystal orientations in series along the out-of-plane direction, and the influence of the microstructural thickness, which indicates the stacking dimension in the out-of-plane direction, was investigated. We compare the macrostructural homogenized material properties between the two- and three-dimensional microstructures.