Estimate by fracture mechanics theory for rolling contact fatigue life and strength of case-hardened gear materials with computer

Abstract The stress intensity range Δk and equation for crack growth da dN = c(Δk) n in linear elastic fracture mechanics was first put forward to calculate the contact fatigue life and strength of case-hardened gear materials in this work. It was found that the ratio of maximum shearing stress S max and hardness H v of the material multiplied by S max , S 2 max / H v , can be regarded as the crack growth driving force; the value of index n is 9 for this kind of material. The calculated results are in good agreement with the experimental data.