Vibration characteristics of composite sandwich plates and layup optimization of their laminated FRP composite faces

This paper examines the vibration characteristics of rectangular, symmetric composite sandwich plates and the layup optimization of their top and bottom laminated FRP composite faces. The honeycomb core is modeled as a thick plate whose transverse shear deformation is taken into consideraion based on a higher-order shear deformation theory, and the top and bottom laminated FRP composite faces are modeled as a very thin sheet. A two-dimensional finite element method is developed using an eight-node isoparametric element. First, the fundamental frequency of the composite sandwich plate is discussed in the subspace of four in-plane lamination parameters of the laminated FRP composite face. Next, the layup optimization of the laminated FRP composite face for maximizing the fundamental frequency of the composite sandwich plate is performed by a nonlinear mathematical programming method, and the optimum laminate configuration of the laminated FRP composite face is determined.