| Budget Amount *help |
¥5,460,000 (Direct Cost: ¥4,200,000、Indirect Cost: ¥1,260,000)
Fiscal Year 2014: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
Fiscal Year 2013: ¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000)
Fiscal Year 2012: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
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| Outline of Final Research Achievements |
The light alloys are promising as future structural material for the automobile. In this study, the fatigue strength characteristics in the very high cycle area, by the surface reforming treatments and by the variable amplitude are investigated. The each mechanism was grasped and the safety improvement in the fatigue strength characteristics is a purpose. From the results of this study, the fatigue strength of light alloys (Al alloy, Mg alloy) is improved in comparison with untreated test specimens and the light alloys was fractured by the fatigue in the very high cycle area. But, in the case that the surface of the specimen developed the roughness or the crack origin developed the inside in the very high cycle life area by the surface reforming treatments, the fatigue strength characteristics are not improved. From the results of the fatigue test by repeated two-step loading, in the testing conditions of this study, the linear cumulative damage rules of all tests were larger than one.
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