The observation and interpretation of crack closure under plain fatigue conditions

Pengbo Qi, Enrico Salvati, Robert Paynter, João Vitor Sahadi Cavalheiro, David Nowell, Alexander M. Korsunsky

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review


This paper reports the results from a set of fatigue experiments carried out on Aluminium alloy 6082-T6 Compact Tension specimens. Crack closure near the tip was observed and interpreted under cyclic loading. In order to interpret the observations, two models were used in the present study, namely, the elastic crack tip field based on the Westergaard stress function approach that provides the expression for crack opening displacement perpendicular to the crack path; and the second model based on elastic-plastic assumptions, as proposed by Pommier. With the introduction of plastic length ρ, both the elastic and plastic contributions to crack tip strain are accounted for. Digital Image Correlation and conventional strain gauges were used to monitor crack closure. For interpretation in terms of the stress intensity factor (SIF), excluding DIC markers lying very close to the crack tip was found to improve the accuracy.

Original languageEnglish
Title of host publicationProceedings of the World Congress on Engineering 2018, WCE 2018
EditorsDavid WL Hukins, Andrew Hunter, Len Gelman, A. M. Korsunsky, S. I. Ao
PublisherNewswood Limited
Number of pages3
ISBN (Electronic)9789881404893
Publication statusPublished - 2018
Externally publishedYes
Event2018 World Congress on Engineering, WCE 2018 - London, United Kingdom
Duration: 4 Jul 20186 Jul 2018

Publication series

NameLecture Notes in Engineering and Computer Science
ISSN (Print)2078-0958


Conference2018 World Congress on Engineering, WCE 2018
Country/TerritoryUnited Kingdom


  • Crack closure
  • Crack tip
  • DIC
  • Stress intensity factor


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