FREE-VIBRATION OF SHEAR-FLEXIBLE ANTI-SYMMETRICAL ANGLE-PLY DOUBLY CURVED PANELS

A hitherto unavailable analytical solution to the boundary-value problem of free vibration of an anti-symmetric angle-ply laminated shear-flexible doubly curved shell of rectangular planform is presented. A novel solution methodology, based on a boundary-continuous double Fourier series approach, is developed to solve the eigenvalue problems, involving five highly coupled linear partial differential equations with constant coefficients, resulting from Sanders' FSDT (first-order shear-deformation theory)-based formulation that also includes surface-parallel and rotatory inertias. Numerical results presented in this study exhibit, for the first time, a mode switch of numerically ordered frequencies from transverse to surface-parallel modes with the change of such geometric and material parameters as length-to-thickness ratio, radius-to-thickness ratio and lamination angle. Additionally, these results have been utilized to validate the accuracy of available CLT-based approximate solutions, computed using the Galerkin approach.