Analysis of piezoelectric fiber-reinforced composites with imperfect interface

Abstract

This thesis is concerned with the study of the electroelastic responses in piezoelectric fiber-reinforced composites which are widely used as sensors and actuators due to their instric electro-mechanical coupling properties. General solutions corresponding to an infinite piezoelectric fiber with a vertical body force and an infinite transversely isotropic elastic mediun with a cylindrical hole are derived by using Fourier integral transforms. These general solution are used to solve the mechanical load and electric charge transfer from a cylindrical piezoelectric fiber into a surronding transversely isotropic elastic matrix. the fiber-matrix in terface is considered to be either mechanically perfect or imperfect and either electrically open- or short-circuited. The tree-dimensional axisymmetric interfacial crack in a piezoelectric fiber-reinforced composite is also studied by employing the displacement discontinuity method(DDM) based on the fundamental solutions schemes are confirmed by comparision with the existing solutions. Numerical results indicate that the electroelastic responses of a piezoelectric fiber-reinforced composites are very complicated and significantly influenced by properties of the piezoeelectric fiber and the elastic matrix, electric boundary conditions and interface conditions. Compared to composites of BaTio3 and PZT-6B fibers, the electric field generated in PZT-4 fiber has the highest vaule implying that PZT-4 is more suitable for sensing applications. In addition, the presence of the imperfect interface results in lower axial load transfer to the matrix and hence lower interfacial stresses but a higher fiber vertical electrical field. A Fundamental understanding obtained from the present study is very useful for a better design and developement of 1-3 piezocomposites with enhanced properties for advanced applications.