New direct observations of crack closure processes in Al-Li 2090 T8E41

A. Guvenilir*, T. M. Breunig, J. H. Kinney, S. R. Stock

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

39 Scopus citations

Abstract

Earlier, crack opening as a function of position within an optically opaque notched tensile sample (NT-3) of Al-Li 2090 was reported for four loads by Guvenilir and co-workers; these measurements were made with high-resolution X-ray computed tomography. This paper reports the same type of results for a second notched tensile sample (NT-4): the authors believe this to be the second sample whose crack closure was quantified as a function of position. The crack within NT-4 was found to be more planar than, and to close differently to, that in NT-3. In NT-4, the crack 'zipped' shut from the tip; this is in contrast to the earlier results on the asperity-dominated crack in NT-3, where contact occurred primarily behind the open crack tip. During unloading of NT-4, the crack faces came into contact above the closure load defined by the intersection of tangent lines to the upper and lower portions of the load-deflection curve; this is similar to previous observations in sample NT-3. Estimates of da/dN as a function of ΔΚ for samples NT-3 and NT-4 agree with others' measurements, which suggests that the closure observations of this paper also apply to compact tension samples of Al-Li 2090.

Original languageEnglish (US)
Pages (from-to)2755-2775
Number of pages21
JournalPhilosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences
Volume357
Issue number1761
DOIs
StatePublished - Jan 1 1999

Keywords

  • Aluminium
  • Crack closure
  • Crackface geometry
  • Fatigue
  • X-ray computed tomography

ASJC Scopus subject areas

  • Mathematics(all)
  • Engineering(all)
  • Physics and Astronomy(all)

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