T-stress effects on fatigue crack growth – Theory and experiment

•Fatigue crack growth tests were performed on four different Al 7075-T6 specimens.•Specimens could provide a wide range of negative and positive T-stresses.•The fatigue crack growth rates were considerably geometry-dependent.•A K-T strain energy density criterion was proposed for predicting crack gr...

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Bibliographic Details
Published in:Engineering fracture mechanics 2018-01, Vol.187, p.103-114
Main Authors: Ayatollahi, M.R., Rashidi Moghaddam, M., Berto, F.
Format: Article
Language:English
Subjects:
Aluminum base alloys
Crack propagation
Cracks
Criteria
Fatigue crack growth
Fatigue failure
Fatigue life
Fatigue tests
Flux density
Fracture mechanics
Generalized strain energy density criterion
Geometry effects
High cycle fatigue
Materials fatigue
Specimen geometry
Strain
T-stress
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Summary:•Fatigue crack growth tests were performed on four different Al 7075-T6 specimens.•Specimens could provide a wide range of negative and positive T-stresses.•The fatigue crack growth rates were considerably geometry-dependent.•A K-T strain energy density criterion was proposed for predicting crack growth rates.•Proposed criterion provided significantly better estimates for test data than the conventional model. The effects of specimen geometry on the fatigue crack growth rate and the number of elapsed cycles have been investigated experimentally and theoretically for Al 7075-T6 using four different cracked specimens with positive and negative T-stresses. All the specimens have been tested under high cycle fatigue loading. An energy-based method, namely the generalized strain energy density (GSED) criterion has been proposed to estimate the fatigue crack growth rate and the number of elapsed cycles by considering the T-stress effects. It is shown that the proposed criterion can provide significantly improved predictions for the fatigue crack growth behavior of the pre-cracked specimens.
ISSN:0013-7944
1873-7315
DOI:10.1016/j.engfracmech.2017.10.025