Fatigue failure of sandwich beams with face sheet wrinkle defects

Martin Leong*, Christian F. Hvejsel, Ole T. Thomsen, Erik Lund, Isaac M Daniel

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

12 Scopus citations

Abstract

This paper presents experimental fatigue results for GFRP face sheet/balsa core sandwich beams with face sheet wrinkle defects, subjected to fully reversed in-plane fatigue loading. An estimate of the fatigue design limit is presented, based on static test results, finite element analyses and application of the Northwestern University failure criteria. The presence of a wrinkle defect reduced the fatigue life by approximately 66%, compared to that of an unnotched reference laminate. Furthermore, the results from the fatigue tests revealed that the design limit was initially overestimated, as the specimens loaded close to the predicted design limit typically failed before reaching the target life, or reached test run-out with visible face sheet damage indicating imminent final failure in the worst case. It was found that specimens would reach target life with no visible or otherwise detectable damage by lowering the fatigue load amplitude below 80% of the predicted design limit. By extrapolating the test results it appears that the undamaged specimens would reach a fatigue life of 10 7-10 8 load cycles and would thus be safe for design of wind turbine blades.

Original languageEnglish (US)
Pages (from-to)1539-1547
Number of pages9
JournalComposites Science and Technology
Volume72
Issue number13
DOIs
StatePublished - Aug 22 2012

Keywords

  • B. Defects
  • B. Fatigue
  • C. Failure criterion
  • C. Finite element analysis (FEA)
  • C. Sandwich structures

ASJC Scopus subject areas

  • Engineering(all)
  • Ceramics and Composites

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