We have used the plane strain theory of transversely isotropic bodies to study a piezoelectric cantilever. In order to find the general solution of a density functionally gradient piezoelectric cantilever, we have used the inverse method (i.e. the Airy stress function method). We have obtained the stress and induction functions in the form of polynomials as well as the general solution of the beam. Based on this general solution, we have deduced the solutions of the cantilever under different loading conditions. Furthermore, as applications of this general solution in engineering, we have studied the tip deflection and blocking force of a piezoelectric cantilever actuator. Finally, we have addressed a method to determine the density distribution profile for a given piezoelectric material.

The interfacial behaviour of fibre-reinforced composites subjected to tension fatigue loading is studied based on the shear-lag model. The governing equations of this problem are obtained and solved. In order to describe the interfacial debonding, the Paris fatigue crack growth formula as well as a modified degradation model fo the coefficient of friction is adopted. Finally some important values related to interfacial debonding are obtained, In the present investigation, Poisson's contraction is considered

Interfacial fatigue of reinforced concrete under tension fatigue loading is simulated based on the shear-lag model. The effects of degradation of concrete strength, the loading frequency and the stress ratio as well as corrosive environment on the interfacial fatigue are considered and discussed. It is found that: (1) degradation of concrete strength and corrosive environment result in opposite effects on interfacial fatigue. (2) Degradation of concrete strength will result in larger effects on interfacial damage in low stress ratio than that in high stress ratio. (3)With a decrease of loading frequency, interfacial corrosion damage will remarkably increase though loading frequency has a small effect on fatigue crack growth in inert media.

Summary In the present paper, the problem of a functionally graded piezoelectric cantilever beam subjected to different loadings is studied. The piezoelectric beam is characterized by continuously graded properties for one elastic parameter and the material density. A pair of stress and induction functions in the form of polynomials is proposed and determined. Based on these functions, a set of analytical solutions for the beam subjected to different loadings is obtained. As particular cases, series of solutions for some canonical problems can be directly obtained from the solutions of the present paper, such as for the problems of a piezoelectric cantilever beam with constant body force or without body forces, etc.

Micromechanical damage of fiber/matrix interface under cyclic loading is simulated. The effects of loading conditions and shear deformation of matrix on interfacial debonding are considered and discussed. It is found that: (1) the force of interfacial fraction plays an important role in resisting interfacial debonding; (2) no matter what kind of the commonly considered loading conditions is, interfacial debonding always undergoes three stages though the damage degree is not the same; (3) the shear deformation of matrix has the ability to slow down the interfacial debonding rate.