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FATIGUE CRACK GROWTH UNDER MIXED MODES I AND II
Author(s) -
Yokobori A. Toshimitsu,
Yokobori Takeo,
Sato Kiyoshi,
Syoji Kazuo
Publication year - 1985
Publication title -
fatigue and fracture of engineering materials and structures
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.887
H-Index - 84
eISSN - 1460-2695
pISSN - 8756-758X
DOI - 10.1111/j.1460-2695.1985.tb00430.x
Subject(s) - materials science , paris' law , crack closure , composite material , crack growth resistance curve , phase (matter) , growth rate , mixed mode , shear (geology) , ultimate tensile strength , structural engineering , fracture mechanics , mathematics , geometry , physics , quantum mechanics , engineering
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 d a /d N = A(ΔK) m , d a /d N at first decreases with increasing Δ K 110 component and then approaches a minimum close to the value of Δ K 110 /Δ K 10 ∼ 0.58; here Δ K 110 /Δ K 10 is the ratio of the initial Δ K II to the initial Δ K 1 ., When Δ K 110 /Δ K 10 increases further, d a /d N increases. Under shear mode, d a /d N becomes higher than that under mode I. The Δ K 1 , and Δ K 11 components during fatigue crack growth under mixed mode loading increase and decrease, respectively, with an increase in d a /d N In the low crack growth rate region the fatigue crack growth rates accelerate with an increase of the initial Δ K 11 component, Δ K 110 . Fatigue life increases with increase of Δ K 110 /Δ K 10 under the test condition of equivalent stress range being kept constant and the pre‐crack length being the same.