Dynamic Response of a Rotating Multi-Span Shaft with Elastic Bearings Subjected to a Moving Load

This paper studies the dynamic response of a rotating multi-span shaft with elastic bearings subjected to an axially moving load. The moving load is motivated by the cutting forces in machining process. The multi-span shaft with elastic bearings models a system that a rotating shaft is mounted by the tailstock and chuck and the steady rests are installed between the ends of shaft. The tailstock and steady rest are modeled as the translational springs and the chuck is assumed as the combination of the translational and rotational springs. The system equations of motion are derived based on the global assumed mode method. The numerical results are obtained to examine the effects of the moving speed of the load, the rotational speed of the shaft, the number of spans, and the stiffnesses of the translational and rotational springs. The numerical results show that the deflection of shaft under the moving load significantly decreases due to the intermediate supports. Moreover, the dynamic behaviors of shaft will be similar when the stiffness of translational spring exceeds the critical stiffness value.