Non-destructive analysis of surface-induced fatigue: Characterisation of micropitting and crack formation

Abstract In this article, a non-destructive, microstructural analysis method for the detailed investigation of surface fatigue, such as micropitting, using optical 3D scans is presented. The data obtained by this method is used to define parameters that describe the surface change in detail and to differentiate micropitting. Hence, the identification of pit locations and other characteristics, such as pit depth, inclination angle, and pit volume, is developed from the surface topology. The method is also used to describe surface fatigue following a micropitting test on a large-module gear, revealing a correlation between the pit characteristics and the path of contact. In particular, the pit depth and the inclination angle, which are determined in each mesh position, reflect the results from microsection analyses. Furthermore, the gear teeth surface is analysed using a replicating compound, showing analogous results. Consequently, the method allows for easy and in-situ determination of micropitting characteristics, eliminating the need for extensive analyses.