Study On The Coupled Field Of Functionally Gradient Piezoelectric Cantilevers

Piezoelectric materials have been widely utilized in sensors or actuators and researched in smart structures. In order to achieve high control forces, high efficiency and high reliability, people need to further study the new piezoelectric materials and structures. Therefore, multilayered piezoelectric devices are designed. However, in these devices the bonding layer may crack at low temperature or peel off at high temperature, which will reduce the lifetime and reliability of piezoelectric devices. In order to solve this problem, these piezoelectric devices are gradually designed with one-or two-dimensional gradients. That is, people suggest that "Piezoelectric Material" is replaced with "Functionally Gradient Piezoelectric Material", and has achieved better results.A lot of new problems must be solved for functionally gradient piezoelectric materials which can be used in engineering. In this paper, the piezothermoelastic cantilevers subjected to different coupled loadings are studied based on the theory of elasticity. That is, seeking the solutions that cantilevers subjected to thermal or electric loadings. The present works include: (1) an analytic solution for the bi-morph piezothermoelastic cantilever is obtained with the theory of elastic, and verify the numerical solution; (2) an analytic solution for a typical multilayered structures is obtained with the theory of elastic, and verify the numerical solution.; (3)an exact solution for a functionally graded beam is obtained with the theory of elastic, and verify the numerical solution.To piezoelectric materials or piezoelectric devices, the gradient property of piezoelectric parameters g₃₁ is basic physical parameters. So in this paper analysis, we focus on the effect of three material parameters (piezoelectric parameters g₃₁,thermal strainμ₁ and the coefficient of thermal conductivity k₃₃) to coupled fields. That is, only these three material parameters are changed independently in different layers of piezoelectric cantilevers, other material parameters are assumed to be constants.In one word, the present investigation will be easily used to identify solutions which are gained from cantilever's subjecting to some typical loadings.