Fatigue of adhesively bonded epoxy-AA6061T651 joints: Fatigue crack propagation and S-N behaviours
International Journal of Structural Integrity
ISSN: 1757-9864
Article publication date: 4 December 2017
Abstract
Purpose
Adhesively bonded joints are gaining importance in the structural joining processes competing against welding and bolting processes. However, long-term behaviour of adhesively bonded joints is still an open question. Due to the increasing interest in adhesively bonded joints, mainly in the transports industry, there is a need to deep the knowledge about the fatigue behaviour of adhesive joints with metallic substrates allowing the development of reliable joints to resist cyclic loadings. The paper aims to discuss these issues.
Design/methodology/approach
An experimental research aiming at characterizing the fatigue behaviour of adhesively bonded aluminium substrates is presented in this paper, covering both fatigue crack propagation and global S-N behaviours. Double cantilever beam (DCB), end notch flexure (ENF) and double lap joints (DLJ) specimens built using the AA6061T651 substrate and epoxy adhesive were used to evaluate the pure modes I and II fatigue crack propagation rates and the S-N fatigue behaviours.
Findings
DCB and ENF specimens allowed the formulation of pure modes I and II fatigue crack propagation laws including the propagation thresholds. DLJs showed higher static shear strength than recommended by the manufacturer for aluminium substrates, but fatigue resistance of the DLJs was lower than suggested by the manufacturer. The fatigue damage process in the DLJs was dominated by a fatigue crack initiation process.
Originality/value
A consistent fatigue research on adhesively bonded aluminium substrates is presented covering in the same study aspects of fatigue crack propagation and fatigue crack initiation. Data reduction schemes involving both numerical and analytical procedures were followed. Proposed work constitutes a rigorous basis for future fatigue prediction models developments.
Keywords
Acknowledgements
The authors acknowledge the Portuguese Science Foundation (FCT) for the financial support through the post-doctoral Grant No. SFRH/BPD/107825/2015. The authors gratefully acknowledge the funding of SciTech – Science and Technology for Competitive and Sustainable Industries (NORTE-01-0145-FEDER-000022), R&D project cofinanced by Programa Operacional Regional do Norte (“NORTE2020”), through Fundo Europeu de Desenvolvimento Regional (FEDER).
Citation
Campos, A.A.M.A., Jesus, A.M.P.d., Correia, J.A.F.O. and Morais, J.J.L. (2017), "Fatigue of adhesively bonded epoxy-AA6061T651 joints: Fatigue crack propagation and S-N behaviours", International Journal of Structural Integrity, Vol. 8 No. 6, pp. 707-724. https://doi.org/10.1108/IJSI-08-2017-0048
Publisher
:Emerald Publishing Limited
Copyright © 2017, Emerald Publishing Limited