著者

植木 洋輔

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.81, no.821, pp.14-00225, 2015 (Released:2015-01-25)

参考文献数

7

被引用文献数

1

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The objective of this study is to establish a methodology for high-speed fatigue testing, especially for resin materials, which includes fiber reinforced composites. To exert periodic stress on a material at a frequency of more than 200 Hz, a specimen was fixed as a cantilever to an electromagnetic vibrator and vibrated in its resonant frequency of the 1st bending mode by using a resonance tracking control. The shape of a specimen made of glass fiber-epoxy laminate was designed with finite element vibration analysis to obtain a resonant frequency of more than 200 Hz and a desired strain distribution for inducing fatigue damage under a certain stress level. A rise of temperature during the fatigue testing due to damping loss was estimated with a heat transfer theory and suppressed by external cooling to keep the specimen at a normal temperature. To confirm the validity of the high-speed testing, a completely reversed bending test at 1 Hz with identical specimens was also performed. Results both from testing at 230 Hz and 1 Hz were plotted on a single power-law curve in an S-N plot, which is a well-known fitting for fiber reinforced composites. This result suggests that we can evaluate fatigue strength in the high- or giga-cycle region for resin and composites in a very short time if temperature is controlled appropriately.