Free Vibration Analysis of Multilayer Skew Sandwich Spherical Shell Panels with Viscoelastic Material Cores and Isotropic Constraining Layers

The present work focuses on the damping of skew sandwich shell panels having multiple layers of viscoelastic material (VEM) core constrained by as many elastic layers under free vibration. The elastic layers kinematics assume first-order shear deformation theory (FSDT) of the shell and have independent transverse displacements, whereas the displacements of the VEM core layers vary linearly with the thickness coordinate. In addition to the transverse shear deformation of the core layers, longitudinal and transverse normal deformations are also taken into account. Numerical analyses are carried out using finite element method to establish the influence of different system parameters such as core layer thickness ratio, constraining layer thickness ratio, aspect ratio on the modal frequencies, and corresponding structural loss factors of the multilayer skew sandwich shell panels under various end restraints.