Stress Intensity Factors for Small Cracks in the Rim of Disks and Rings Subjected to Rolling Contact

Abstract

The influence of the residual stresses attending the plastic deformation of a rim on the cyclic crack growth driving force produced by repeated two-dimensional rolling contacts is evaluated. The residual stresses are estimated for disks and rings with different geometries. Values of the Mode II and Mode I stress intensity range, ΔKI and ΔKII , are derived for small, subsurface cracks from the variations in the stress intensity factors with position of the contact for rolling in the absence of surface shear tractions. The calculations take into account (i) steady-state contact stresses generated by a relative peak pressure of po /k = 5; (ii) the radial and circumferential residual stresses, (iii) the frictional resistance on the crack faces; (iv) the crack inclination, and (v) the relative ratios of the inner and outer ring radii. A prediction of the crack initiation and growth rate for high strength steel is illustrated.