Evaluating stress intensity factors of a surface crack in lubricated rolling contacts

摘要

The three-dimensional finite element method andthe least-squares method were used to find the stress intensityfactors (SIFs) of a surface crack in a lubricated roller. A steelroller on a rigid plane was modeled, in which a semi-ellipticalsurface crack is inclined at an angle ψ to the vertical axis. Adistance C is set between the crack base and the roller edge. Theresults indicate that the mode-I SIF reaches the maximum valuewhen the angle θ is equal to 0° (on the roller surface), and themode-II SIF reaches the absolute maximum value when the angleθ is near or equal to 90° (inside the roller), where θ is the angleof the semi-ellipse from 0° to 180°. The influence of mode-IIISIFs in this model is minor since they are much smaller than themode-I and mode-II SIFs. The SIFs increase greatly when thecrack location approaches the uncrowned edge. At this time, acrowned profile can be used to significantly reduce the SIFs nearthe roller edge.