Vibration Analysis of Coupled Double- Nanocomposite Microplate-systems

The aim of the paper is to analyze electro-thermo nonlinear vibration of a double-piezoelectric composite microplate-system (DPCMPS) based on nonlocal piezoelasticity theory. The two microplates are assumed to be connected by an enclosing elastic medium which is simulated by Pasternak foundation. Both of smart composite microplates are made of poly-vinylidene fluoride (PVDF) reinforced by zigzag double walled boron nitride nanotubes (DWBNNTs). The micro-electromechanical model is employed to calculate mechanical, thermal and electrical properties of composite. Using nonlinear strain-displacement relations and considering charge equation for coupling between electrical and mechanical fields, the motion equations are derived based on energy method and Hamilton s principle. These equations can t be solved analytically due to their nonlinear terms. Hence, differential quadrature method (DQM) is employed to solve the governing differential equations for the case when all four ends are clamped supported and free electrical boundary condition. The frequency ratio of DPCMPS is investigated for three typical vibrational states, namely, out-of-phase, in-phase and the case when one microplate is fixed in the DPCMPS. A detailed parametric study is conducted to scrutinize the influences of the small scale coefficient, stiffness of the internal elastic medium, the volume fraction and orientation angle of the DWBNNTs reinforcement, temperature change and aspect ratio. The results indicate that with increasing geometrical aspect ratio, the effect of coupling elastic medium between two smart nanocomposite microplates reduces. This study might be useful for the design and smart control of nano/micro devices such as MEMS and NEMS.