Parametric analysis of frequency of rotating laminated composite cylindrical shells with the wave propagation approach

The vibration analysis of rotating laminated composite cylindrical shells using the wave propagation approach is presented. Results obtained using the approach have been evaluated against those available in the literature and a good agreement has been found. The present approach is a simple, non-iterative and effective method. With the present method the influence of the shell parameters, the axial mode m, the circumferential mode n, the thickness-to-radius ratio h/R, the length-to-radius ratio L/R, the rotating speed Ω (rps) and the boundary conditions on the natural frequencies, is investigated. At low circumferential mode n, the stationary frequency is between the frequencies for forward and backward whirl modes. But at high circumferential mode n, the stationary frequency is smaller than both the forward and backward frequencies. The backward frequency is always higher than the forward frequency, however, the difference between the backward and forward frequencies reduces as the mode n increases. The backward frequency increases monotonically with the increase of rotating speed Ω. The forward frequency reduces with the increase of rotating speed Ω at lower m and n modes but increases at higher m and n modes. The difference between the forward and backward frequencies increases with the increase of rotating speed Ω. The boundary conditions considered are clamped/clamped, clamped/simply supported, simply supported/simply supported, and clamped/sliding conditions. The influence of boundary conditions on the frequencies is more significant at small circumferential mode n. The transition of fundamental frequency from the higher mode n curve to the lower mode n curve takes place at different h/R ratios for different boundary conditions. The frequency decreases as the length parameter L/R increases, but the reduction is more obvious at low L/R ratios. For any L/R ratios, the stationary frequency is between the forward and backward frequencies. The difference between the forward and backward frequencies increases as the L/R increases.