Distortion and residual stresses in structures reinforced with titanium straps for improved damage tolerance

C. D.M. Liljedahl, M. E. Fitzpatrick, L. Edwards

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

Distortion and residual stresses induced during the manufacturing process of bonded crack retarders have been investigated. Titanium alloy straps were adhesively bonded to an aluminium alloy SENT specimen to promote fatigue crack growth retardation. The effect of three different strap dimensions was investigated. The spring-back of a component when released from the autoclave and the residual stresses are important factors to take into account when designing a selective reinforcement, as this may alter the local aerodynamic characteristics and reduce the crack bridging effect of the strap. The principal problem with residual stresses is that the tensile nature of the residual stresses in the primary aluminium structure has a negative impact on the crack initiation and crack propagation behaviour in the aluminium. The residual stresses were measured with neutron diffraction and the distortion of the specimens was measured with a contour measurement machine. The bonding process was simulated with a three-dimensional FE model. The residual stresses were found to be tensile close to the strap and slightly compressive on the un-bonded side. Both the distortion and the residual stresses increased with the thickness and the width of the strap. Very good agreement between the measured stresses and the measured distortion and the FE simulation was found.

Original languageEnglish
Pages (from-to)104-111
Number of pages8
JournalMaterials Science and Engineering A
Volume486
Issue number1-2
Early online date3 Oct 2007
DOIs
Publication statusPublished - 15 Jul 2008
Externally publishedYes

Keywords

  • Bonded crack retarder
  • Finite element analysis
  • Neutron diffraction
  • Residual stresses

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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