Geometrically Nonlinear Vibration of Laminated Composite Plates Fitted With Piezoelectric Actuators and Subjected to Thermal Environments

Abstract

Laminated composite plates have found widespread applications in the construction of engineering structures due to the several attributes of the composites such as light weight, high specific strength, high specific stiffness as well as excellent fatigue and corrosion resistance properties. Plates are used in structural applications either as main structures or as structural components. All structures are exposed to varying thermal conditions during their service life. The degraded material properties as well as the residual stresses generated due to the elevated temperature conditions influence the vibration behavior considerably. As a result the effect of thermal environment on the static and dynamic behavior of laminated composite plates needs to be studied thoroughly.
When the transverse vibrations of a uniformly heated structure is studied using the linear theories, the thermal effect is converted into a body force and the results show negligibly small variation as compared to those of a structure without any temperature change. Therefore, nonlinear analysis methods need to be applied to analyze the behavior.
This project reports the nonlinear free vibration characteristics of laminated composite plates which are bonded with piezoelectric actuator layers. The plates are subjected to thermal environment in addition to the electric load. The finite element method (FEM) is employed for the analysis. An eight-noded isoparametric Co continuity element with five degrees of freedom per node is used taking into consideration von Karman large deflection assumptions. The governing differential equations are obtained using the modified first-order shear deformation plate theory (MFSDT). The formulation includes the effects of transverse shear, in-plane and rotary inertia. The nonlinear matrix amplitude equation obtained by employing the Galerkin’s weighted residual method is solved using the direct iteration technique. Detailed parametric studies are carried out to investigate the effect of different parameters on the free vibration characteristics of laminated plates.
The finite element codes are accordingly developed in MATLAB. The validity of the present finite element code is demonstrated by comparing the present results with the solutions available in the literature. Then the study is further extended to investigate the effect of different parameters such as temperature rise, control voltage, boundary conditions, fibre orientation and stacking sequence on the free vibration behavior of laminated composite plates fitted with piezoelectric actuators and subjected to thermal environments.