疲労き裂伝ぱ速度の試験片内変動と試験片間変動の分離 : ΔK一定試験による検討(<小特集>信頼性工学小特集)

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The purpose of this paper was to decompose experimentally the variability of the fatigue crack propagation rate da/dN into two parts, the inter-specimen variability and the intra-specimen variability. Specifically, in order to separate σ_b^2 and σ_w^2 experimentally, fatigue crack propagation tests were conducted under the condition of constant ΔK, where σ_b^2 and σ_w^2 were the inter-specimen variance and the intra-specimen variance of log da/dN, respectively. The condition of constant ΔK was attained by use of the tapered double cantilever beam specimens. The material tested was the high strength steel HT 60. By measuring the increment of the crack length Δa at regular cycle intervals of ΔN, da/dN was evaluated as da/dN=Δa/ΔN as in usual cases. ΔN was chosen as ΔN=5000 cycles. The technique of analysis of variance was applied to the test data to estimate σ_b^2 and σ_w^2. It was shown that σ_b^2 and σ_w^2 were of the same order. The F test also showed that the inter-specimen variabili
社団法人日本材料学会の論文
1987-09-15