Numerical simulation of kink angle prediction for non-lubricated surface crack subjected to Hertzian pressure

Analysis of determining linear fracture mechanics parameters for a surface crack loaded with Hertzian pressure without the presence of a lubricant in the crack is presented. For this purpose, the elements of Williams equation for describing stresses near the crack tip are determined: Stress intensity factors KI and KII, and T-stress, which were taken into account when determing the direction of crack propagation by means of Strain energy density (SED) criterion. The elements are determined based on the case of a gear tooth flank, with various friction coefficients on the free surface and friction in the crack being taken into account. The results show that friction on the free surface and, consequently, tangential forces have an impact on whether the crack will propagate along the free surface or into the depth