Fatigue life recovery via laser shock peening in mechanically damaged aluminium sheet; experiments and prediction models

Niall Smyth, Philip E. Irving

Research output: Chapter in Book/Report/Conference proceedingConference proceeding

1 Citation (Scopus)

Abstract

This paper reports the effectiveness of residual stress fields induced by laser shock peening (LSP) to recover pristine fatigue life. Scratches 50 and 150 μm deep with 5 μm root radii were introduced into samples of 2024-T351 aluminium sheet 2 mm thick using a diamond tipped tool. LSP was applied along the scratch in a band 5 mm wide. Residual stress fields induced were measured using incremental hole drilling. Compressive residual stress at the surface was -78 MPa increasing to -204 MPa at a depth of 220 μm. Fatigue tests were performed on peened, unpeened, pristine and scribed samples. Scratches reduced fatigue lives by factors up to 22 and LSP restored 74% of pristine life. Unpeened samples fractured at the scratches however peened samples did not fracture at the scratches but instead on the untreated rear face of the samples. Crack initiation still occurred at the root of the scribes on or close to the first load cycle in both peened and unpeened samples. In peened samples the crack at the root of the scribe did not progress to failure, suggesting that residual stress did not affect initiation behaviour but instead FCGR. A residual stress model is presented to predict crack behaviour in peened samples.

Original languageEnglish
Title of host publication11th International Fatigue Congress
PublisherTrans Tech Publications
Pages980-985
Number of pages6
Volume891-892
ISBN (Print)9783038350088
DOIs
Publication statusPublished - Mar 2014
Externally publishedYes
Event11th International Fatigue Congress, FATIGUE 2014 - Melbourne, Australia
Duration: 2 Mar 20147 Mar 2014

Publication series

NameAdvanced Materials Research
Volume891-892
ISSN (Print)1022-6680

Conference

Conference11th International Fatigue Congress, FATIGUE 2014
CountryAustralia
CityMelbourne
Period2/03/147/03/14

Keywords

  • 2024-T351 aluminium sheet
  • Fatigue
  • Laser shock peening
  • Mechanical scratch damage
  • Scribe

ASJC Scopus subject areas

  • Engineering(all)

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