Influence of specimen type and reinforcement on measured tension-tension fatigue life of unidirectional GFRP laminates

Research output: Contribution to journalArticle


  • Samuli Korkiakoski
  • Povl Brøndsted
  • Essi Sarlin
  • Olli Saarela

Research units

  • Technical University of Denmark
  • Tampere University of Technology


It is well known that standardised tension-tension fatigue test specimens of unidirectional (UD) glass-fibre-reinforced plastics (GFRP) laminates tend to fail at end tabs. The true fatigue life is then underestimated. The first objective of this study was to find for UD GFRP laminates a test specimen that fails in the gauge section. The second objective was to compare fatigue performance of two laminates, one having a newly developed UD powder-bound fabric as a reinforcement and the other having a quasi-UD stitched non-crimp fabric as a reinforcement. In the first phase, a rectangular specimen in accordance with the ISO 527-5 standard and two slightly different dog-bone shaped specimens were evaluated by means of finite element modelling. Subsequent comparative fatigue tests were performed for the laminates with the three specimen types. The results showed that the test specimen type has a significant effect on the failure mode and measured fatigue life of the laminates. A significantly higher fatigue life was measured for the laminate with the powder-bound fabric reinforcement when compared to the laminate with the stitched reinforcement.


Original languageEnglish
Pages (from-to)114-129
Number of pages16
Publication statusPublished - 1 Apr 2016
MoE publication typeA1 Journal article-refereed

    Research areas

  • Fatigue test methods, Polymer matrix composites, S-N curves, Specimen design, Unidirectional laminate

ID: 1707726