FREE-VIBRATION OF THIN-WALLED COMPOSITE BLADES

Theoretical analysis for predicting the natural frequencies and mode s hapes of rotating thin-walled composite beams is presented. The struct ural modeling is based on a systematic reduction of a comprehensive st ructural formulation which contains a detailed description of the out- of-plane warping. The resulting equations describe the dynamics of the axial displacements, two transverse displacements and the twist angle , and are formulated as a standard eigenvalues problem. Coupled modes in symmetric and antisymmetric box-beams are clearly identified and di scussed. The results are correlated with other theoretical predictions and provide an additional insight into the vibration characteristics of rotating composite beams.