X-Ray Investigation on the Prediction of Fatigue Life : On the Changes in Half-Value Breadth of Carbon Steel under Varying Stress Amplitudes

Abstract

It has been reported by the authors that the estimation of fatigue life of the materials under constant stress amplitude can be made using the liner relation of b/B-logn/N (where B and b are the initial and the current half-value breadth of diffraction line in fatigue and n/N is the cycle ratio). In the present paper, the following experiments were performed ; the first, the experiments were made on the case of varying stress amplitude of two stress levels above fatigue limit and investigated the change of half-value breadth due to varying stress amplitude. The second, the half-value breadth was measured by using satisfactory method in physical meaning and compared with the conventional method which has been adopted in these series of investigations. Finally, discussed on a change of half-value breadth under varying stress amplitude and postulated a certain method for nondestructive estimation of fatigue life.