深い切欠きをもつ高強度鋼材の疲労き裂の発生

概要

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The behavior of fatigue crack initiation in a deep notched specimen of Ni-Cr-Mo high strength steel is studied using the apparent stress intensity factor K_a which is obtained by substituting the notch length for the crack length in the equation of stress intensity factor K. The results obtained are as follows: (1) When the notch root radius ρ is constant, the number of cycles at fatigue crack initiation N is decided by the range of apparent stress intensity factor ΔK_a regardless of the notch length a_0. (2) At constant ΔK_a, N decreases with decreasing ρ. The thickness of specimen, B, has no effect on the relation betweenΔK_a and N. (3) The notch opening displacement φ depends only on the apparent stress intensity factor K_a, but not on a_0 and ρ. (4) The fatigue crack initiation life of a notched specimen with arbitrary a_0, ρ and B under arbitraryΔK_a can be predicted from the relation between the strain range and N of smooth specimens, by relating φ with the strain at the notch root.
社団法人日本材料学会の論文
1976-03-15