Abstract Gears are used in high power density (power throughput/weight) machines for continuous power transmission. The efficiency and reliability of gears significantly depend on tribological performance. Micropitting is a type of rolling contact fatigue damage mechanism that occurs at the asperity scale in lubricated contacts and highly prevalent in gears. A detailed surface characterization study is essential to get an insight into the incident of micropitting. In this work, factors affecting resistance to micropitting are investigated by performing series of twin disk experiments. The effect of disc geometry and slide-to-roll ratio on resistance to micropitting is discussed in detail. It is observed that micro pits coalesces occur when components run for very large number of fatigue cycles. A positive correlation is found between autocorrelation length and surface damage. Rose plot and area-scale fractal analysis is employed on damaged surfaces, and it is concluded that there exists a certain scale, below which fractal theory is applicable.

中文翻译：

---

基于分形方法的接触疲劳损伤实验分析

摘要 齿轮在高功率密度（功率吞吐量/重量）机器中用于连续动力传输。齿轮的效率和可靠性在很大程度上取决于摩擦学性能。微点蚀是一种滚动接触疲劳损伤机制，它发生在润滑接触的粗糙尺度上，在齿轮中非常普遍。详细的表面表征研究对于深入了解微点蚀事件至关重要。在这项工作中，通过执行一系列双盘实验来研究影响抗微点蚀的因素。详细讨论了圆盘几何形状和滑辊比对抗微点蚀的影响。据观察，当部件运行非常大量的疲劳循环时，会出现微坑合并。在自相关长度和表面损伤之间发现正相关。对损伤表面进行玫瑰图和面积尺度分形分析，得出存在一定尺度的结论，在该尺度下，分形理论是适用的。