Effective Electroelastic Properties of a Piezocomposite with Viscoelastic and Dielectric Relaxing Matrix

Abstract

We use the correspondence principle of linear viscoelasticity and the Mori-Tanaka averaging method to determine the effective electroviscoelastic moduli of a piezocomposite made of piezoceramic (PZT) inclusions and a viscoelastic matrix whose dielectric constants also vary with time t. For elliptic cylindrical PZT inclusions, closed form expressions for the electroviscoelastic moduli are derived. It is found that for the 1-3 piezocomposite, the relaxation of the dielectric constants of the matrix affects only the dielectric moduli and the shear components of the piezoelectric and the viscoelastic moduli of the piezocomposite. However, the viscoelasticity of the matrix influences every effective electroelastic modulus of the piezocomposite. The relaxation times of any two effective moduli are different, and the piezocomposite is an orthotropic material. For time-harmonic loading of the piezocomposite studied, only frequencies in the range of 10 2- 102 Hz strongly influence the effective storage and the effective loss moduli. Whereas thin PZT ribbons provide the most mechanical strength to the piezocomposite, they give the least piezoelectric effect.