This paper presents the effect of coupling between bending and torsional deformations on vibrations of composite Timoshenko beams from the wave standpoint. The dispersion characteristics and the modes of vibrations are in general affected by material coupling, except those of the torsional modes at low frequencies; and higher-frequency modes are normally more sensitive to material coupling. The wave mode transition phenomenon is also investigated. It is found that like their metallic counterparts, composite Timoshenko beams also exhibit wave mode transition. Furthermore, the transition frequency is found to be unaffected by material coupling. Numerical examples for which comparative results are available in the literature are presented.

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