Dynamic effects of bulge interface fretting wear on elastic ring squeeze film dampers

Elastic Ring Squeeze Film Dampers (ERSFDs) are complex damping structures governed by fluid-structural interaction. Fretting wear at the bulge interfaces of ERSFDs, introduced by periodic frictional sliding, is a critical factor affecting the dynamic behavior of high-speed rotating machinery, thereby threatening the long-term reliability. This study presents a comprehensive investigation into this dynamic behavior, unveiling the mechanism through which wear-induced changes in contact mechanics and oil flow regions lead to dynamic performance loss. To analyze this phenomenon, a novel fluid-structural interaction model is proposed, which uniquely integrates the worn bulge geometry to simulate its influence on oil film dynamics. This numerical approach is coupled with extensive experimental validation on a Jeffcott rotor rig, where dampers were run for up to 10⁷ cycles. The analysis reveals that wear is a highly non-uniform fretting process, with material loss concentrated at the circumferential and axial edges of the bulges due to localized pressure. Detailed microscopic characterization of the worn surfaces identified complex damage patterns, including abrasion, adhesion, plastic flow, and spalling. It was found that this progressive material loss creates bypass leakage paths between oil film chambers, compromising the damper’s sealing integrity. The resulting degradation of the damper’s dynamic properties was quantified both numerically and experimentally, demonstrating a significant reduction in dynamic stiffness and damping coefficients as operational cycles increased. This research establishes a direct link between interfacial fretting wear and the functional degradation of ERSFDs, offering critical insights for the life assessment and wear-resistant design of these vital components.