Dynamical response of the shaft-bearing system of marine propeller shaft with velocity-dependent friction

摘要

The appropriate assessment of dynamical response of the marine propeller shaft is essential to enable optional power delivery to propeller and to minimize friction of supporting bearings. Abnormal shaft vibration induced by the interaction of water-lubricated stern bearings seriously affect the reliability of marine propulsion system during ships' navigation. An applicable numerical model regarding dynamical response of the shaft-bearing system considering velocity-friction interaction is proposed. The cooperative Newton-Raphson & Newmark-beta iterative method is applied to solve this nonlinear model with velocity-dependent friction. To capture the nature of shaft-bearing interaction, the dynamical response of shaft relative velocity, bearing reaction force and dynamic friction coefficient with various model parameters are obtained. The influence of rotational speed, stick factor and slip factor regarding velocity-dependent friction on the dynamical response is discussed with data comparison in detail. The residual force defined in theoretical basis is also analyzed for each Case to certificate the reliability of the numerical calculation. A comparison of the Poincare surface between present work and previous reference is conducted to validate the applicability of the proposed frictional model. The optimized design for marine propeller shaft and water-lubricated stern bearings is thus realized based on the adjustment of material friction properties.