STRUCTURAL MODELING AND FREE-VIBRATION ANALYSIS OF ROTATING COMPOSITETHIN-WALLED-BEAMS

A refined theory of rotating blades modeled as thin-walled composite b eams of arbitrary closed cross-sections is presented and used to study their free vibration behavior, The structural model encompasses a num ber of non-classical features such as the anisotropy and heterogeneity of constituent materials, transverse shear, primary and secondary war pings and includes the effects of the centrifugal and Coriolis force f ields, It is shown that in the context of a special ply angle configur ation and when Coriolis effects are discarded, the governing system of equations splits exactly into two independent systems, describing the flap-lag-transverse shear and extension-twist motions, It is also rev ealed that the structural model developed in this paper contains, as s pecial cases, a number of cases described in the literature, The excel lent agreement between the results available in the literature and the ones obtained in the context of the present developed model is report ed. Numerical illustrations showing the influence of the ply orientati on and angular velocity on the flap-lag-transverse shear and twist-ext ension coupled free vibration eigencharacteristics are presented and t he benefits of exploiting the induced elastic couplings are highlighte d.