変動荷重を受ける切欠き材の疲労強度 : S35C材, K_t=3,5の場合(<小特集>X線材料強度小特集)

概要

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Previously the authors carried out fatigue tests under such conditions as (1) variable loadings, (2) superposed waveform loadongs and (3) intermittent waveform loadings, and applied these test results to estimate the fatigue lives of actual machines. Aithough many fatigue test results have been published, the data for notched specimens, especially in the case of rotating bending, about crack initiation and crack propagation under variable loadings are very few. Therefore, in order to contribute to the study of this problem, the authors have carried out the fatigue tests for the notched specimens under two-level multiple block loadings. The conclusions obtained from the test results are summarized to the following two points. (1) Modified Miner's law predicts the fatigue life too short, especially in the long life range. (2) It is, for the time being, a neccessary and inevitable expedient to predict the fatigue life by extending the S-N curve downward in a atraight line and by adopting σ_<eq>^* and Σn_iin which n_2^β is substituted for n_2 in the conventional formulas of equivalent stress σ_<eq> and total repeated numbers Σn_i.
社団法人日本材料学会の論文
1987-08-15