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組合応力状態におけるα-黄銅の疲労被害


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Title: 組合応力状態におけるα-黄銅の疲労被害
Other Titles: Fatigue Damage of α-brass under Combined Stress States
Authors: 眞武, 友一
Authors (alternative): Matake, Tomokazu
Issue Date: Dec-1973
Publisher: 長崎大学工学部 / Faculty of Engineering, Nagasaki University
Citation: 長崎大学工学部研究報告, (4), pp.1-12; 1973
Abstract: There are many methods to research the fatigue damage on the view point of micro-state and macro-state. However, it is the interesting method, as the intermediate state between them, to remove periodically the surface layer of the specimen after stressing, within which the fatigue damage may be concentrated. In this paper, the author mentions the fatigue damage ofα-brass specimen by the method of stressing-annealing-electropolishing. The specimen is experimented under the stress states of torsion, bending and two combined states of these stresses. Now, we define the repetitions, until the time when such a phenomenon is observed that the crystalline fatigue crack begins to propagate to the neighbour grain, as 'the standard damage life,N0' . It is necessary to remove the thin surface layer to confirm N0, as we cannot observe them on the surface of the specimen only, especial1y under torsion. If N1 is the number of stress repititions during one period, the thickness of the damaged layer increases proportional1y to increasing of the ratio, N1/N0 under every stress state. Then it is concluded that the generalized Miner's law is correct by introducing the standard damage life, N0. If σn and τmax are the normal and shearing stress on the plane of maximum shearing stress and N0 is suffixed τ under torsion, the ratio N0/N0τ is independent of the stress levels, and is constant in the case of the constant value of σn/τmax. And the standard damage life N0 under any stress state is deduced from Noτ. Therefore, under any stress level and any stress state, the thickness of the damaged layer at any stress repetitions wi11 be presumed.
URI: http://hdl.handle.net/10069/23799
ISSN: 02860902
Type: Departmental Bulletin Paper
Text Version: publisher
Appears in Collections:No.4

Citable URI : http://hdl.handle.net/10069/23799

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