Vibration Reduction Performance of Damping-Enhanced Water-Lubricated Bearing Using Fluid-Saturated Perforated Slabs

Abstract As the first link element for the transmission of shaft vibration to the pedestal and even to the hull, water-lubricated bearing plays a key role in suppressing vibration. Although the porous structure is considered as one of the main methods for improving the wideband vibration and noise reduction performance of materials in many industrial fields, the studies in the field of water-lubricated bearing remain insufficient. To enhance vibration reduction performance, a fluid-saturated perforated slab is designed in this study, and via the establishment of a fluid-solid coupled vibration model, the influence law and impact levels were analyzed and verified by simulation and experiments. The results obtained verified that the total vibration amplitude of damping-enhanced stern bearing in the vertical direction was smaller than that of the normal stern bearing, and the reduction amplitude of the characteristic frequency agreed with the optimal value at approximately 0.1 of the volume fraction of the liquid phase when the solid-fluid phase was rubber–water. Additionally, the increase in fluid fraction did not enhance the damping effect, instead, it unexpectedly reduced the natural frequency of the raw material significantly. This research indicates that the design of the fluid-saturated perforated slab is effective in reducing the transmission of the vibration amplitude from the shaft, and presents the best volume fraction of the liquid phase.