Tribological Properties And Wear Prediction Of Water-lubricated Polymer Materials Of Stern Tube Bearings

The stern tube bearing is the key support and vulnerable component of the ship propulsion system,so the reliability of its performance directly affects the safety and economy of the ship.As a moving part of ship,wear failure is the main form of stern tube bearing.It is of great engineering and practical significance to study the friction and wear characteristics of stern tube bearing and predict its life.In this paper,plastic,resin fiber and rubber materials as the research object,focusing on the friction and wear mechanism of stern tube bearing made of 3 kinds of materials in different loads,different speed and different lubrication conditions,by comparing and analyzing the friction coefficient,wear quality,surface morphology and other information,the wear form of the polymer materials stern tube bearing in different working conditions is speculated.Using laser interferometric surface profilometer and VHX-2000 ultra-depth microscope to observe the surface characteristics of the specimens after wear,and provide the theoretical basis for theoretical inference.The influence of material,load and rotation speed on the wear is explored by the mathematical method of orthogonal test.An empirical formula for the reliability life of water-lubricated polymer materials stern tube bearing was established based on mathematical methods such as Weibull distribution and maximum likelihood estimation.In this paper,the experiments were first designed based on the actual operating conditions of the stern tube bearing.The tests were performed on the CBZ-1 friction and wear tester and the SSB-100 test bench.Plastics,resin fibers,rubber materials,and cast copper were selected as friction pairs.The changing laws of friction coefficient and wear amount under different materials,different loads,and different rotation speeds were analyzed in two lubrication states: water-dilution and dry-friction.The reason for the change in friction coefficient and wear volume was explored.The results show that the friction and wear properties of plastic materials are the best,followed by resin fiber materials,and the friction and wear properties of rubber materials are the worst.The mathematical method of orthogonal test was used to explore the influence of the three kinds of experimental factors,such as the material,speed,and load on the amount of wear,was investigated under water lubrication conditions.The results showed that the three kinds of factors had no significant effect on the wear of the tail bearing,the degree of impact by large to small are material,speed,and load,respectively.Combined with the observation of the surface morphology of the friction pair after wear,the main wear patterns of the stern tube bearing under different working conditions were analyzed.The results showed that the wear patterns of the three kinds of materials under the condition of water lubrication were relatively stable,in the state of dry friction,the wear form is closely related to the material,load,and rotation speed.Based on Weibull distribution,an evaluation formula for the reliability life of water-lubricated polymer materials stern tube bearing is established.The results show that the fault distribution function and the empirical fault distribution function fit well and can be applied to the evaluation of the average life,rated life and median life of water-lubricated polymer materials stern tube bearing,providing theoretical support for the safe maintenance of water-lubricated polymer materials stern tube bearing.