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High‐stress fatigue crack propagation in thin AA2024‐T3 sheet material
Author(s) -
Breitbarth Eric,
Strohmann Tobias,
Requena Guillermo
Publication year - 2020
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/ffe.13335
Subject(s) - materials science , paris' law , stress intensity factor , crack closure , aluminium , composite material , stress (linguistics) , aluminium alloy , stress concentration , tension (geology) , fatigue testing , fracture mechanics , fuselage , structural engineering , damage tolerance , digital image correlation , metallurgy , ultimate tensile strength , engineering , linguistics , philosophy , composite number
Fatigue crack growth in 1.6‐mm‐thick sheets of aluminium alloy AA2024‐T3 was investigated under very high‐stress conditions using 950‐mm‐wide middle tension (MT) specimens. Experiments were conducted by applying uniaxial load ratios R (0.1, 0.3 and 0.5) with the maximum nominal stress of 120 MPa following conditions relevant for aircraft fuselage structures. The experiments were conducted with digital image correlation to determine loading conditions acting on the crack tip. Stable crack growth rates of up to d a /d N > 4 mm/cycle and Δ K > 100 MPa√m were reached, and final crack lengths 2 a > 500 mm were obtained. High‐stress intensity factors cause plastic zone sizes that extend up to approximately 100 mm from the crack tip. The d a /d N ‐Δ K data obtained in this study provide crucial information about the fatigue crack growth and damage tolerance of very long cracks under high‐stress conditions in thin lightweight structures.