Requirements and variability affecting the durability of bonded joints

Rhys Jones, Daren Peng, John G. Michopoulos, Anthony J. Kinloch

Research output: Contribution to journalArticleResearchpeer-review

5 Citations (Scopus)

Abstract

This paper firstly reveals that when assessing if a bonded joint meets the certification requirements inherent in MIL-STD-1530D and the US Joint Services Standard JSSG2006 it is necessary to ensure that: (a) There is no yielding at all in the adhesive layer at 115% of design limit load (DLL), and (b) that the joint must be able to withstand design ultimate load (DUL). Secondly, it is revealed that fatigue crack growth in both nano-reinforced epoxies, and structural adhesives can be captured using the Hartman-Schijve crack growth equation, and that the scatter in crack growth in adhesives can be modelled by allowing for variability in the fatigue threshold. Thirdly, a methodology was established for estimating a valid upper-bound curve, for cohesive failure in the adhesive, which encompasses all the experimental data and provides a conservative fatigue crack growth curve. Finally, it is shown that this upper-bound curve can be used to (a) compare and characterise structural adhesives, (b) determine/assess a "no growth" design (if required), (c) assess if a disbond in an in-service aircraft will grow and (d) to design and life in-service adhesively-bonded joints in accordance with the slow-growth approach contained in the United States Air Force (USAF) certification standard MIL-STD-1530D.

Original languageEnglish
Article number1468
Number of pages23
JournalMaterials
Volume13
Issue number6
DOIs
Publication statusPublished - 2 Mar 2020

Keywords

  • A4EI
  • CMH-17-3G
  • JSSG-2006
  • MIL-STD-1530D
  • Operational aircraft
  • PABST
  • Variability in fatigue crack growth

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