抄録
In the previous papers, some of the present authors reported the test carried out of the repeated tension impact about unnotched specimens of some metals to find the impact fatigue curves for wider ranges of the number of repetitions, and clarified the discontinuity of their curves.
In this paper, we have performed similar tests about the specimens which had various circumferential notches made respectively of 0.17%C steel, 0.82%C steel and copper, covering the number of repetitions N=1∼106 in order to study the effects of notch on impact fatigue curves.
The summary of the experimental results is as follows;
(1) Like the impact fatigue curves of unnotched specimens in the previous paper, the curves of notched specimens consists of two curves, one is plastic fatigue curve, the other is true fatigue curve, which are found to be discontinuous.
(2) The impact value at N=1 decreases when the radius ρ of notch becomes smaller. The plastic fatigue curves start from the impact value at N=1 for each type of the specimen, and at small number of repetitions they cross over each other as shown in Figs. 2, 12 and 16.
(3) The impact fatigue strength at N=105∼106 in the true fatigue region are estimated from the results of the experiments as shown in Tables IV. V and VI.
