COMPETITION BETWEEN FATIGUE CRACK-PROPAGATION AND WEAR

Based on a semi-empirical derivation of the Paris fatigue law, the fatigue crack length a is related to the yield limit or flow stress, which ultimately is related to the hardness of the material. The analysis considers together the cyclic loading, which tends to increase the surface crack length, and the wear, which tends to decrease the crack length at the surface, and shows that under certain conditions a stable crack length may be developed. Experiments conducted on two test groups ((i) R(c) = 58.5 and (ii) R(c) = 62.7) tend to support the present analysis.