Fatigue crack growth behaviour under mixed modes I and II was studied by applying in‐phase alternating tensile and torsional loading to a thin‐walled hollow cylindrical specimen with an initial crack. In the linear region of a log‐log plot where da/dN=A(ΔK)m, da/dN at first decreases with increasing ΔK110 component and then approaches a minimum close to the value of ΔK110/ΔK10∼ 0.58; here ΔK110/ΔK10 is the ratio of the initial ΔKII to the initial ΔK1., When ΔK110/ΔK10 increases further, da/dN increases. Under shear mode, da/dN becomes higher than that under mode I. The ΔK1, and ΔK11 components during fatigue crack growth under mixed mode loading increase and decrease, respectively, with an increase in da/dN In the low crack growth rate region the fatigue crack growth rates accelerate with an increase of the initial ΔK11 component, ΔK110. Fatigue life increases with increase of ΔK110/ΔK10 under the test condition of equivalent stress range being kept constant and the pre‐crack length being the same.
|ジャーナル||Fatigue & Fracture of Engineering Materials & Structures|
|出版ステータス||Published - 1985 4|
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