Study On Mechanical Behaviors And Size Effect Of 0-3 Polarized PLZT Plate

As a new emerging smart material,PLZT photoelectric ceramic material will produce the deformation along the polarization direction when it is illuminated by specific wavelength light,which is named Photostrictive Effect.In recent years,micro-actuators and micro-sensors made by PLZT has become a new interesting research hotspot in the field of MEMS due to the special energy conversion mechanism which can be used in non-contact remote operations without the hard wiring.The design and manufacture of MEMS are in the micron size.But numerous experiments have shown that the mechanical properties of the materials in micron size are obviously different from those in macro size,exhibiting the size effect.The existence of the size effect has severely hindered the application of PLZT photoelectric ceramics in MEMS.The classical elastic theory is not able to explain size effects in micro-structures because of the lack of material length scale parameter.This paper will make a deep investigation on the size effect of PLZT in in the micron size based on the new modified couple stress theory.Based on the new modified couple stress theory and von Karman's geometric nonlinearity,the size-dependent model for nonlinear static bending analysis of a pure 0-3 polarized PLZT plate is developed for the first time.The equilibrium equations of the pure 0-3 polarized PLZT plate are derived from a variational formulation based on the potential energy principle.The Galerkin method is adopted to derive the nonlinear algebraic equations from equilibrium differential equations and then the nonlinear algebraic equations are solved by using Newton–Raphson method.After simplification,the new model includes only a material length scale parameter and can reduce to the classical elastic theory model.And then the numerical simulations are carried out to study the effect of size effect on the nonlinear deformation of a simply supported pure 0-3 polarized PLZT plate subjected to light illumination and uniform distributed load.The numerical results indicate the new model is able to capture the size effect and geometric nonlinearity.In order to study the ability of driving and shape control of the 0-3 polarized PLZT driver in micro size,a static bending model of 0-3 polarized PLZT laminate plate including couple stress is established.The effect of material length scale on the deformation of a 0-3 polarized PLZT laminated simple supported plates is analyzed.Finally,the driving and controlling effects of different plane dimensions,different thickness and different positions of the 0-3 polarizing PLZT driver on the microplate are discussed.