Fretting Fatigue in SUP9 Spring Steel Under Random Loading

Abstract

The fretting fatigue strength of SUP 9 spring steel under random loading was examined by clamping the contact pads of the same material. Random loading reduced the fretting fatigue strengths by a factor of 1.5. The linear cumulative damage rule held well for fretting fatigue under random loading. The relationship between the coefficient of the friction and the slip amplitude using root-mean-square values under random loading agreed well with that under constant amplitude loading. Prediction of fatigue life was made on the basis of the fracture mechanics analysis proposed in the previous paper, where the frictional force between the fretting pad and the specimen was taken into consideration. The predicted lives were in good agreement with the experimental results.