Vibration analysis and critical speeds of polar orthotropic annular disks in rotation

An application of composite materials to rotating disks is proposed to increase the critical speed. Dynamic equation is formulated by the Rayleigh–Ritz method in order to calculate the natural frequency and critical speed for rotating composite disks. The orthogonal functions are used for series solution. Fibers could be aligned in radial or circumferential directions to have polar orthotropy in circular disk. The results show that the circumferentially-reinforced disk is more effective in increasing critical speed than the radially-reinforced disk. The circumferentially-reinforced CFRP CD is shown to have the five times higher critical speed than that of the polycarbonate CD.