著者

真壁 朝敏 S. M. Moshiar RAHAMAN 名嘉 海人 真鍋 光輝

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会九州支部講演論文集

巻号頁・発行日

vol.2021, 2021

著者

RAHMAN S. M. MOSHIAR 名嘉 海人 真壁 朝敏

出版者

一般社団法人 日本高圧力技術協会

雑誌

圧力技術 (ISSN:03870154)

巻号頁・発行日

vol.59, no.2, pp.52-60, 2021

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There is a good correlation between the <I>S</I>-<I>N</I> curve and crack growth law in carbon steel. Also, the fatigue limit of that can be evaluated from the param-eters of hardness and crack initiation conditions. The crack initiation behavior is related to the distribution of microstructures and the sizes of inclu-sions. Therefore, when the fatigue limit and life of carbon steel are predicted, it is better to consider the initial crack length and crack growth behavior. In this study, one such case was investigated by push-pull with constant stress amplitude by using 0.45% carbon steel. The initial crack lengths were varied with the specimen used and testing conditions. The prediction method of the <I>S</I>-<I>N</I> curve from a corrected crack growth law in such case was pro-posed. Also, a method of prediction of fatigue limit and life from the point of safety was discussed in this study.

著者

ラーマン エス エム モシアール 真壁 朝敏 名嘉 海人 山内 章広

出版者

一般社団法人 日本高圧力技術協会

雑誌

圧力技術 (ISSN:03870154)

巻号頁・発行日

vol.58, no.4, pp.209-215, 2020

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There is a good correlation between the static strength and fatigue limit in many carbon steels. However, in the case of some commercially sold carbon steel, the fatigue limit cannot be evaluated from the static strength. Care should be taken when those materials are used for ma-chine equipment. In the case of some materials, there is decrease in fa-tigue limit from the expected values of Vickers hardness. In this study, one such case was investigated by push-pull. The examinations of the <I>S</I>-<I>N</I> curves and crack growth behavior were performed. Then, it was discussed that decrease in fatigue limit was related to the existence of inclusions or defects of unexpectedly large size. When such material as used in the present study is used for a machine equipment, the decrease of fatigue limit should be taken into account to determine an applied load.