The effective electroelastic moduli of textured piezoelectric polycrystalline aggregates

The effective electroelastic moduli of textured piezoelectric polycrystalline aggregates have been modeled by the self-consistent approach and traditional Voigt-Reuss averages. The orientational averaging scheme in textured piezoelectric polycrystals has been developed using the orientation distribution function (ODF), which can be done analytically with a series of generalized associated Legendre functions, or numerically with the Gaussian quadrature method. Gaussian distribution function has been adopted to simulate a wide range of textures in piezoelectric polycrystals, and a key parameter alpha is identified to be closely related to the processing conditions such as poling field intensity. Numerical results are presented and discussed for poled and unpoled BaTiO3 ceramics, and BaTiO3 films with perfectly aligned grains, which agree well with known theoretical results. It is found that the electroelastic moduli of piezoelectric polycrystalline aggregates show strong dependence on texture; piezoelectric constants higher than the corresponding single crystal values can be achieved at certain texture; and dielectric constants are more sensitive to grain shape than elastic constants. (C) 2000 Elsevier Science Ltd. All rights reserved.