On the free-vibration of rotating composite beams using a higher-order shear formulation

The free vibration behavior of rotating blades modeled as laminated composite, hollow (single celled) boxed beams is investigated. To this end, geometrically nonlinear structural model incorporating a number of non- classical effects such as anisotropy, heterogeneity, transverse shear flexibility, and warping inhibition is developed. Centrifugal and Coriolis force field effects are also considered in the formulation. However, Coriolis effect is discarded during the solution process. It is assumed that in-plane cross-sectional distortion is negligible. In contrast to the existing structural blade models, the traction free boundary conditions on the external surfaces of the beam are identically satisfied. The linearized dynamical equations and numerical results addressing the problem of the free vibration are supplied. Results obtained for the present higher-order shearable model are compared with those of the existing first-order shearable and the non-shearable structural models. Tailoring studies using the present model reveal an enhancement of eigenfrequency characteristics.