Free vibration analysis of deep doubly curved soft-core sandwich panels with different boundary conditions

Abstract

This paper presents a free vibration analysis of deep doubly curved soft-core sandwich panels where the face sheets are made of laminated composite, and the core is considered to be compressible. The compressibility of the core is formulated using the Extended Higher-Order Sandwich Panel Theory (EHSAPT). Accordingly, the first-order shear deformation theory is used to model the face sheets, and third- and second-order functions are used to model the in-plane and transverse displacements of the core, respectively. The equations of motion and relevant boundary conditions are derived using Hamilton’s principle. The Rayleigh-Ritz method with single series expansions with two-variable orthogonal polynomials as trial functions is employed to obtain the panel's natural frequencies and mode shapes. Convergence and comparison studies are carried out to demonstrate the efficiency and accuracy of the solution, and the method is validated against the results obtained through different approaches in the literature. Finally, a parametric study illustrates the effect of various parameters on vibration characteristics of cylindrical and spherical sandwich panels with different boundary conditions, which may be used as benchmark results for future studies.