Vibration analysis of rotating composite shafts containing randomly oriented reinforcements

The vibration behaviors of the rotating composite shafts containing randomly oriented reinforcements are studied in this paper. The Mori–Tanaka mean-field theory is adopted here to account for the interaction at the finite concentrations of reinforcements in the composite material. The effective elastic moduli of the composite material are expressed as a function of the phase properties, volume fraction, orientation angles of its constituents. The finite element model of the rotating continuous fiber-reinforced composite shafts derived previously by authors is extended here to the case that contains the fiber inclusions by taking these effective elastic moduli into account. Based on this model, the natural frequencies of the stationary shafts, and the whirling speeds as well as the critical speeds of the rotating shafts are investigated. The results reveal that the content and the orientation of reinforcements have great influence on the dynamic characteristics of the composite shafts.