Experimental and theoretical studies on ferroelastic switching of 1-3 type piezocomposites

A systematic investigation of the stress-dependent non-linear electromechanical properties of 1-3 piezocomposites for different fiber volume fractions and bulk piezoceramics is carried out. Experiments are conducted to measure the electrical displacement and longitudinal strain on piezocomposites and bulk ceramics under uni-axial compressive stress loading conditions. A simplified uni-axial micro-macro-mechanical model based on thermodynamic framework is developed to predict the behaviour. Volume fractions of three distinct uni-axial variants (instead of six variants) are used as internal variables to describe the microscopic state of the material. In order to calculate the effective properties (elastic, piezoelectric and dielectric constants) of piezocomposites for different fiber volume fractions, an analytical model based on equivalent layered approach is proposed. The predicted effective properties are incorporated into uni-axial model and the classical stress versus strain and stress versus electrical displacement curves are simulated. Comparison between the experiments and simulations show that the proposed model can reproduce the characteristics of non-linear coupled response. It is observed that, the variation in the fiber volume fraction has a significant influence in the response of 1-3 piezocomposites.