Koo K.

Rotating disks are widely used in the data storage devices such as CDs, DVDs(digital versatile disks), and HDs(hard disks) as well as in the traditional machines such as circular saws, turbines, and so on. Since fiber reinforced composite materials has high specific strength and stiffness, an application of fiber reinforced composite materials to rotating disks can enhance the performance of machinery by saving the driving energy and increasing the rotation speed. There have been few works on the vibration characteristics of rotating multidirectional laminated disks made of fiber-reinforced composite materials. Most of the previous researches have been confined to single lamina disks. When a disk rotates, the centrifugal force causes the in-plane loads which affect on the vibration characteristics of rotating disk. In this paper, the exact expressions for the in-plane loads acting on rotating cross-ply laminate disk are presented. The vibration equation of rotating cross-ply laminate disk is solved by the Galerkin method. In the numerical analysis, the natural frequencies and critical speeds of rotating disks are discussed for various cross-ply ratios.