Applying multiaxial fatigue criteria to standing contact fatigue

The ability of some multiaxial fatigue criteria to predict initiation of st anding contact fatigue cracks is investigated. In the standing contact fati gue test an indenter subjects a case-hardened rest specimen to a stationary but pulsating contact load. The initiation of two axi-symmetric crack type s appearing in the test specimen is investigated. The surface initiated rin g/cone cracks circumscribe the contact area, whereas the lateral cracks are horizontal sub-surface cracks. The effect of the stress-state history at p ossible crack Locations is evaluated through the Sines, Haigh principal str ess, Findley, Me Diarmid and Dang Van multiaxial fatigue criteria. The mate rial fatigue parameters of each criterion are determined from independent b ending and torsion fatigue testing. Finally, the mean and spread in radial position of the ring/cone crack are evaluated by considering the statistica l effects of a weakest link assumption using a three parameter Weibull dist ribution. The investigation shows that it is hard to distinguish a single c riterion that well describes all aspects of the experimental results. For t he current contact situation with highly compressive mean stresses in combi nation with tensile maximum values the Findley criterion shows the best ove rall performance followed by the Haigh principal stress criterion. (C) 2001 Elsevier Science Ltd. All rights reserved.