3416 結晶均質化法による圧電材料のマルチスケール最適設計(S15-1 先端材料,S15 先端材料システムの強度・機能評価とメゾメカニックス)

抄録

In order to improve piezoelectric response of polycrystals in a macro scale, micro distribution of crystal orientations was optimized by using multiscale finite element method based crystallographic homogenization theory. As a result, two noteworthy optimum solutions were obtained for micro structure. One is a polycrystalline structure laminated with three specified grains for macro piezoelectric strain constant d_<333>, the other is a polycrystalline structure consisting of two regularly-neighboring grains with specified orientations for d_<311>. As the maximum micro strain occurs by electric and mechanical effects, the optimized micro structures exhibit the highest macro piezoelectricity that is beyond single crystal. Their micro structures are available for piezoelectric ceramics such as BaTiO_3 and Pb (Zr, Ti)O_3, that have the maximum piezoelectric strain constant under off-axis electric field.