Effects of in-plane constraints on the free vibration of a symmetrically laminated doubly curved panel

Summary. For a symmetrically laminated curved panel, although the stretching-bending anisotropic coupling stiffnesses are zero, but due to presence of the curvature, the in-plane and out-of-plane behaviors of the panel are still coupled, and hence the in-plane constraints at the boundaries have influences on the transverse behavior of the panel. Such effects of in-plane constraints on the free vibration of the symmetrically laminated curved panel are investigated using a modified Galerkin method in this study. Transverse shear deformation of the panel is considered by using first-order shear deformation theory. Numerical results of the symmetric angle-ply and cross-ply laminated panel with simply supported boundary conditions (SS2 and SS3) are presented. Results show that the in-plane boundary constraints have significant effects on the vibration behavior of the symmetrically laminated curved panel, and the effects strongly depend on the radius of curvature, thickness and lamination schemes, etc. Effects of bending-twisting anisotropic coupling of symmetric angle-ply laminate on the vibration behavior are also discussed.