Influence of Debris Dent on EHD Lubrication

Film thickness measurements associated with a debris dent have been made with Interferometry under static and dynamic conditions. The presence of a debris dent alters the shape of the inlet region so that the local film thickness at the leading edge of the dent can become substantially lower than the trailing edge. The pressure modifications associated with these local EHD effects are in line with the frequent occurrence of surface initiated fatigue spalls originating at the trailing edge of debris dents. The effectiveness of the EHD mechanism in reducing the stress concentrations at the shoulders of the dent is related to inlet dimensions and dent size. Presented as an American Society of Lubrication Engineers paper at the ASLE/ASME Lubrication Conference in Boston, Massachusetts, October 5–7, 1976