Simulation of rolling contact fatigue strength for traction drive elements (comparison with fatigue test)

Abstract

A simulation of the rolling contact fatigue strength of a traction drive element was developed. This simulation accounts for both the distribution of sizes of inclusions in the element material and the influence of traction forces at the element surface. The shear strength of the matrix structure surrounding an inclusion was estimated with an equation. The purpose of this report is verifying the estimation accuracy of this simulation by comparing with the experimental result. The experiment was carried out by according to the 14 S-N testing method. The material of test rollers was carburized JIS SCM420H. The hardness distribution and the Weibull distribution of inclusion dimensions, which are necessary parameters of this simulation, were determined by observation of an actual test specimen. The calculated rolling contact fatigue strength in failure rate of 50% at 107 cycles was 750 MPa with a standard deviation of 35.4 MPa. The rolling contact fatigue strength of 1120 MPa with a standard deviation of 50.8 MPa was obtained as a result of experiment. The failure mode was considered to be flaking from the internal origination. The calculated standard deviation was about equal to the experimental result. Though there was 370 MPa difference between calculated and experimental fatigue strength. Including of the hardening of roller and the influence of compressive residual stress in the simulation and the determination of the depth of failure initiation will decrease above error.

Keywords

• machine element
• traction drive
• rolling contact fatigue
• 14 s-n testing method
• inclusion
• tribology
• shear stress