A numerical study about the effects of the metal volume fraction on the effective properties of a porous piezoelectric composite with metalized pore boundaries

Abstract

This work investigates a developed porous piezoelectric composite with metal layers introduced at the interfaces between the piezoelectric and vacuum phases. These metal layers can be added to improve the mechanical and electromechanical properties of the composite. The ordinary porous piezocomposite, which contains only vacuum pores, and the piezocomposite with metal inclusions, whose pores are filled with metal, were explored as specific cases. We constructed the finite element model for all composites understudy and determined their macro properties using the effective moduli theory, which depends on the well-known Hill-Mandel principle. We considered a simple representative unit cell cubic volume, which consists of a piezoelectric matrix with a spherical pore at its center. We compared the properties of all systems and explored the effects of the metal fraction increase on the effective moduli. There are drastic effects on the dielectric permittivity and piezoelectric properties of the considered composite due to the presence of metal inclusion. With an appropriate design of the porous piezocomposite with a metalized pore surface, better effective piezoelectric strain coefficients and transverse transduction coefficient can be achieved. As a result, it is expected that piezoelectric transducers made from this piezocomposite would perform well in piezoelectric motors, transverse piezoelectric sensors, and transverse piezoelectric energy harvesters.