Fatigue crack growth in 7249-T76511 aluminium alloy under constant-amplitude and spectrum loading

From National Research Council Canada

DOIResolve DOI: https://doi.org/10.1111/ffe.12253
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Name affiliation
  1. National Research Council of Canada. Aerospace
FormatText, Article
Journal titleFatigue and Fracture of Engineering Materials and Structures
ISSN8756-758X
Volume38
Issue5
Pages528–539
SubjectAlloys; Aluminum; Aluminum alloys; Amplitude modulation; Crack closure; Crack propagation; Fatigue crack propagation; Fatigue of materials; Fatigue testing; Strain; Stress analysis; Stress intensity factors; Wings; Compression pre crackings; Constant amplitude; Constraint factor; Crack mouth opening displacement; Effective stress intensity factor range; Fatigue-crack-growth tests; Full-scale fatigue test; Spectrum loading; Cracks
Abstract
Fatigue crack growth tests were conducted on compact, C(T), specimens made of 7249-T76511 aluminium alloy. These tests were conducted to generate crack growth rate data from threshold to near fracture over a wide range of load ratios (R). Four methods were used to generate near threshold data: (1) ASTM E-647 load reduction (LR), (2) compression pre-cracking constant-amplitude (CPCA), (3) compression pre-cracking LR, and (4) constant crack mouth opening displacement LR method. A crack closure analysis was used to develop an effective stress-intensity factor range against rate relation using a constraint factor (α = 1.85). Simulated aircraft wing spectrum tests were conducted on middle crack tension, M(T), specimens using a modified full-scale fatigue test spectrum. The tests were used to develop the constraint-loss regime (plane strain to plane stress; α = 1.85 to 1.15) behaviour. Comparisons were made between the spectrum tests and calculations made with the FASTRAN life prediction code; and the calculated crack growth lives were generally with ±10% of the test results.
Publication date
PublisherWiley
LanguageEnglish
Peer reviewedYes
NPARC number21275715
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Record identifier675672da-b322-4bba-8651-716e824dc405
Record created2015-07-14
Record modified2020-04-22
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