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THE EFFECT OF REGULAR AND IRREGULAR SHEAR LIPS ON FATIGUE CRACK GROWTH IN Al 2024
Author(s) -
Zuidema J.,
Krabbe J. P.
Publication year - 1997
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.1460-2695.1997.tb01499.x
Subject(s) - shear (geology) , materials science , crack closure , composite material , paris' law , fracture mechanics
— Multiple underloads and overloads with constant Δ K were carried out on centre‐cracked tension specimens. It was found that when shear lips develop, underloads or overloads affect the crack growth rate d a /d N and the subsequent retardation. The appearance of the shear lip fracture surfaces depends on the frequency. At higher frequencies a greater number of rough shear lip fracture surfaces will develop, while at lower frequencies there is a tendency towards smooth shear lips. The amount of crack closure differs in each case. It was found that the type of shear lip, rough or smooth, can be related to the effect on d a /d N during and after underloads. The effect of rough and smooth shear lip growth was investigated in constant Δ K tests, performing these tests with and without crack closure.