Investigation into the Dynamic Parameter Characterization of Water-Lubricated Bearings Under Vibration Coupling

This study aims to investigate the dynamic behavior of water-lubricated stern bearings during service. A transient rotor dynamics numerical model is developed to research the effects of operating conditions and critical structural parameters on the variation patterns of the dynamic characteristic coefficients and journal orbit of WLBs. The main stiffness and damping formulas for dimensionless bearings are fitted based on numerical results. Additionally, the accuracy of the model calculations is experimentally verified on a water-lubricated bearing test rig. The results demonstrate that the variation trends of the main stiffness and main damping coefficients in the horizontal and vertical directions of the bearings are proportional to the external load and inversely proportional to the rotational speed. Under eccentric excitation, the dynamic characteristic coefficients of the bearings change periodically with time as an approximately sinusoidal function. With the increase in the bearing length-to-diameter ratio or the decrease in the radial clearance-to-radius ratio, the main stiffness and the main damping coefficients in the horizontal direction increase, while the main stiffness coefficient in the vertical direction decreases. This study provides theoretical support for modeling the transient transverse vibration of a propulsion shaft system.