The effects of strain hardened layer on pitting formation during rolling contact

The role of the strain hardened layer playing in pitting formation during rolling contact is analyzed using the fracture mechanics approach. The other governing factors are the initial crack length, crack angle, contact force, friction on all contact surfaces, and the hydraulic pressure of trapped fluid acting on the crack surfaces. Mode I and II stress intensity factors and the strain energy density factors are calculated by application of the two-dimensional finite element method. The strain energy density theory is applied to show the coupling effects between the hardened layer and the other factors. All analytical results predicted in this paper agree well with the experimental observations.