Wear Evolution and Reliability Assessment of Bottom-Pivot Friction Pairs in Miter Gates

The bottom pivot of a miter gate operates underwater under low-speed, heavy-load, and reciprocating-sliding conditions, where lubrication deterioration can accelerate local wear and increase operating resistance. Conventional hinge-based models cannot describe the transient contact and wear behavior of this component. In this study, a global–local finite element model integrating the full gate structure and the three-dimensional bottom-pivot friction pair was developed. Nonlinear contact theory and Archard’s wear model were used to evaluate contact pressure, equivalent stress, sliding behavior, and wear accumulation during complete opening and closing processes. The results show that high-stress and high-wear regions are concentrated in the upper contact zone of the bearing bush, which exhibits higher stress and greater cumulative wear than the mushroom head. Although acceleration and deceleration induce transient stress peaks, the constant-velocity stage contributes most to wear because of its longest sliding duration. The closing process produces greater wear than the opening process. A preliminary mechanics-to-reliability linkage was explored by extrapolating single-cycle wear to cumulative degradation. A three-parameter Weibull model fitted to 22 field replacement-cycle records yielded a mean replacement cycle of approximately 14.5 × 104 operations. The proposed framework provides a mechanics-informed basis for bottom-pivot inspection, lubrication management, and maintenance planning.