Modelling of the effective linear behaviour of piezoelectric ceramics

Abstract

The paper focuses on the overall linear elastic, piezoelectric and dielectric response of polycrystalline piezoelectric ceramics. The effective material behaviour is calculated using the effective medium approximation and taking into account the domain structure of the crystallites. The model considers the full electromechanical interaction coupling of the grains with their surroundings in a statistical way. The actual domain structure depends on crystallite orientation and applied load, leading to the minimum of potential energy of the system. Thus, the model gives the possibility to predict intrinsic as well as extrinsic contributions to the linear behaviour of piezoelectric ceramics. Numerical results for the effective properties of unpoled and poled BaTiO₃ ceramics are presented. They show a strong effect of extrinsic contributions to the effective dielectric and piezoelectric constants.

Keywords:

• piezoceramics
• effective properties
• domain structure