Hu Yuantai

An exact analysis of forced thickness-twist vibrations of multi-layered piezoelectric plates

This paper deals with the thickness-twist vibration of a multi-layered rectangular piezoelectric plate of crystals of 6 mm symmetry or polarized ceramics. An exact solution is obtained from the three-dimensional equations of linear piezoelectricity. The solution is useful to the understanding and design of composite piezoelectric devices. A piezoelectric resonator, a piezoelectric transformer, and a piezoelectric generator are analyzed as examples.

Green's functions of two-dimensional anisotropic body with a parabolic boundary

For two-dimensional anisotropic body with a parabolic boundary, the simple explicit expressions of Greens functions are presented when a concentrated force f is applied at a point (xinf1sup0, xinf2sup0) in material for two kind boundary conditions, which are of free surface and rigid surface. When parabolic curve degenerates into a half-infinite crack or a half-infinite rigid defect the stress singular fields near the crack tip are obtained by using the results obtained. Specially, when the concentrated force f is applied at a point on the parabolic boundary, its Greens functions are studied, too. By them and its integral, the arbitrary parabolic boundary value problems can be solved. The limit case that the boundary degenerates into a crack is studied and the corresponding stress intensity factors are obtained.

Transversely isotropic damage around conducting crack-tip in four-point bending piezoelectric beam

A static damage constitutive model was proposed on basis of the electrical enthalpy density, and then some characteristics of transversely isotropic damage were discussed. Finally, the effects of both crack depth and applied loads on damage distributions were investigated through numerically analyzing transversely isotropic damage in a four-point bending PZT-PIC151 beam with a central conducting crack. Some conclusions were given: 1) Crack depth and mechanical loading have great influence on both mechanical and electrical damages. With their increment, the damages at crack-tip obviously increase and their region sizes also expand. 2) Effects of electrical loading on the two kinds of damages are obviously different. Electrical loading monotonously changes magnitude but region size of mechanical damage, whose effect on electrical damage is very complex.