著者

藤井 朋之 東郷 敬一郎 山本 崇博 鈴木 幸則 島村 佳伸 尾嶋 良文

出版者

公益社団法人 日本材料学会

雑誌

材料 (ISSN:05145163)

巻号頁・発行日

vol.62, no.12, pp.770-777, 2013-12-15 (Released:2013-12-20)

参考文献数

11

被引用文献数

4 5

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In this paper, fatigue tests and finite element analysis are carried out on spot weld-bonded joints of mild steel (270MPa class) and ultra-high strength steel (980MPa class) in order to investigate influence of strength level of base steels on fatigue strength and fatigue fracture behavior of spot weld-bonded joints. From the fatigue tests and finite element analysis, the following results are obtained : (1) The fatigue strength of the spot weld-bonded specimen is higher than that of the spot welded specimen. (2) The fatigue limit of the spot weld-bonded specimens of the ultra-high strength steel is higher than that of the mild steel. (3) The interfacial debonding propagates from the adhesive edge to a nugget edge, and the fatigue crack initiates at the nugget edge in both steels. (4) The fatigue strength of spot weld-bonded specimens is improved because the stress concentration at the nugget edge is reduced by adhesive bonding during large part of fatigue life.

著者

三浦 祐太朗 藤井 朋之 東郷 敬一郎 島村 佳伸

出版者

一般社団法人 日本機械学会

雑誌

東海支部総会講演会講演論文集

巻号頁・発行日

vol.2014, pp._520-1_-_520-2_, 2014

著者

上田 敏郎 島村 佳伸 東郷 敬一郎 藤井 朋之 岡島 いづみ 平松 正敬 佐古 猛

出版者

The Society of Materials Science, Japan

雑誌

材料 (ISSN:05145163)

巻号頁・発行日

vol.59, no.12, pp.964-969, 2010

被引用文献数

2 5

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Carbon-fiber reinforced epoxy was decomposed using subcritical water and supercritical methanol to reclaim carbon fibers. The tensile strength of the reclaimed carbon fibers was measured. Then SEM observation, XPS, and Raman spectral analysis were conducted to elucidate the change of tensile strength caused by decomposition. The tensile strength decreased by 6% in the case of decomposition with supercritical methanol, and by 12~17% with subcritical water. The surfaces of reclaimed carbon fibers were resin-free. Decomposition did not affect the fiber surface and fracture surface morphology. Subsequent XPS analysis revealed that functional groups of the carbon fiber surface had been removed. Raman spectral analysis showed decreased graphitization of the carbon fiber surface. These results imply that the fracture toughness of the carbon fiber surface decreased because of breakage of carbon-carbon bonds in the carbon fibers as a result of decomposition.