Fatigue Life of Metallic Materials under Varying Repeated Stresses of Two Different Stress Waves

TLDR: In this paper, the fatigue tests under varying repeated stresses, which consisted of two different bending stresses (the first and second stress waves), were carried out by the specially designed testing machine, using notched specimens of 0.22 and 0.61 per cent carbon steels and super duralumin.

Abstract: The fatigue tests under varying repeated stresses, which consisted of two different bending stresses (the first and second stress waves), were carried out by the specially designed testing machine, using notched specimens of 0.22 and 0.61 per cent carbon steels and super duralumin. These test results were compared with the calculated ones which predict the fatigue life of metallic materials subjected to such varying repeated stresses. And the following are concluded : (1) The analytical fatigue life of 0.22 per cent carbon steel and super duralumin under the varying repeated stresses has a good agreement with the test results. (2) In the case of 0.61 per cent carbon steel, the second stress wave has no influence on the fatigue life, when the ratio of the second stress wave to the first stress wave, λ, is smaller than about 0.8, and the analytical fatigue lives have a good agreement with the test results, only when λ is greater than about 0.8.