Tribo-Dynamic-Wear coupling analysis for Water-lubricated Bearings with journal surface imperfection under repeated start-stop cycles

Water-lubricated Bearings (WLBs) are the core transmission components of a ship propulsion system, and their wear behavior primarily occurs during the starting and stopping states. To characterize the wear behavior of WLBs, an equivalent experiment is conducted on bush material to obtain the relationship between dimensionless wear coefficient and sliding distance based on the Archard wear model. Then, an experimentally determined transient wear model is incorporated into a tribo-dynamic model to develop a fully coupled Tribo-Dynamic-Wear (TDW) model for the WLBs during repeated start-stop cycles. In this model, the 3D thermal effect, the transient bush worn surface and the geometric imperfection of the journal surface are considered. Numerical results show that the wear rate is more significant at the beginning of the start-up state and the end of the stopping state of the WLB. Meanwhile, it is found that compared to a perfect journal, a reasonable undulation number and undulated amplitude of the journal surface can improve the wear resistance performance of WLBs during repeated start-stop cycles. More specifically, a relatively lower undulation number leads to a smaller wear volume than the perfect journal, and the undulated journal surface has an optimal undulated amplitude that minimizes the wear volume.