弾塑性および全面降伏条件下での疲労き裂伝ぱ則

概要

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The rate of crack propagation was measured in notched specimens of annealed O. 04%C steel in high and low cycle fatigue regimes. Fractographic observation indicated that the single micro-mechanism is responsible for crack growth in the observed range of fatigue crack growth rates of 10^<-6>-10^<-2>mm/cycle. The mechanical parameter which controlled the growth rate was investigated. The growth rate of fatigue crack under large scale and general yielding conditions was found to be higher than that predicted from the power equation between the rate and the stress intensity factor obtained under the condition of small scale yielding. The plastic part of the crack tip opening displacement Δφ_lt;plastic>. and the cyclic J-integral ΔJ were found to be such parameters which gave the single value of the rate da/dN by the following equations : da/dN= 2.66 (Δφ_lt;plastic>) ^<2.15> da/dN= 1.22×l0^<-3> (ΔJ)^<1.35>.
社団法人日本材料学会の論文
1977-01-15