Free vibration analysis of rotating FGP sandwich cylindrical shells with metal-foam core layer

This study offers a unique solution for the free vibration of rotating FGP sandwich cylindrical shells under different boundary conditions. A new type of sandwich structures with a metal-foam core and two coating FGM layers is investigated. Equations of motion governing the free vibration of rotating shells are derived by the first-order, shear-deformation shell theory. Single-term modal functions are introduced in Rayleigh-Ritz method to efficiently determine natural frequencies of the shell. After result validations, the influence of volume fraction index, distribution schemes, core-layer thickness, porosity coefficient, rotating velocity, geometrical parameters, and boundary conditions on the shell natural frequencies are studied.