An Analytical Approach for Free Vibration of Hygrothermal-Electro-elastic Composite Cylindrical Shells

Purpose This paper aims to find exact solutions for the hygrothermal-electro-elastic (HTEE) vibration of functionally graded (FG) piezoelectric composite cylindrical shells. Four distribution patterns of HTEE composites are taken into consideration. Methods A Hamiltonian-based method is introduced to obtain exact solutions for free vibration of FG HTEE cylindrical shells. Unlike the classical Lagrangian system, the governing equations in the Hamiltonian form are solved in a rigorous and straightforward way. Results Exact frequency equations and vibration mode shapes are obtained simultaneously. The accuracy is verified by comparing with the existing results. A comprehensive parametric study is also performed to reveal the effects of geometrical parameters, wave numbers, end conditions, electric voltage, temperature rise and moisture absorption on free vibration behaviors of the FG HTEE cylindrical shells. Conclusion The results show that the geometrical parameter, circumferential wavenumber and end conditions are key influencing factors on the cases of symplectic eigenfunctions. For a specific HTEE cylindrical shell, its fundamental frequency highly depends on end conditions, material properties and hygrothermal-electric loads.