抄録
The effects of stress ratio, ratio of number of cycles and magnitude of applied stress on the fatigue strength of notched medium steel were studied under many-fold multiple rotating bending load in two stress levels. A few other investigators have reported that on the notched specimen the fatigue life is nearly equal to the calculated life by the linear damage law, i.e, Nth=n0/(nA/NA+na/Na). According to the test results the fatigue life on the notched specimen shows the same tendency to change with the stress ratio, the ratio of number of cycles and the magnitude of the applied stress as on the smooth specimen all over the stress range. But the value of N/Nth on the notched specimen seems to be larger than that on the smooth specimen. In the last part of this paper we state the way to modify the linear damage law with the stress correction factors which are the functions of stress ratio, the ratio of number of cycles and magnitude of applied stress. The method makes it possible to deduce the fatigue life under manyfold multiple load with the help of a few experimental data.
