An experimental method to determine the intralaminar fracture toughness of high-strength carbon-fibre reinforced composite aerostructures

H. Liu, B. G. Falzon, G. Catalanotti, W. Tan

Research output: Contribution to journalArticle

6 Citations (Scopus)
190 Downloads (Pure)

Abstract

Carbon fibres with high tensile strength are being increasingly utilised in the manufacture of advanced composite aerostructures. A Modified Compact Tension (MCT) specimen is often deployed to measure the longitudinal intralaminar fracture toughness but a high tensile strength often leads to premature damage away from the crack tip. We present an approach whereby the MCT specimen is supported by external fixtures to prevent premature damage. In addition, we have developed a novel measurement technique, based on the fibre failure strain and C-scanning, to determine the crack length in the presence of surface sublaminate delamination which masks the crack tip location. A set of cross-ply specimens, with a ((90/0)s)4 layup, were manufactured from an IMS60/epoxy composite system Two different data reduction schemes, compliance calibration and the area method, are used to determine the fibre-dominated initiation and propagation intralaminar fracture toughness values. Propagation values of fracture toughness were measured at 774.9 ± 5.2% kJ/m2 and 768.5 ± 4.1% kJ/m2, when using the compliance calibration method and the area method, respectively. Scanning Electron Microscopy (SEM) is carried out on the fracture surface to obtain insight into the damage mechanism of high-tensile-strength fibre-reinforced unidirectional composites. The measured tensile fracture toughness value is used in a fully validated computational model to simulate the physical test.

Original languageEnglish
Pages (from-to)1352-1370
JournalAeronautical Journal
Volume122
Issue number1255
Early online date30 Jul 2018
DOIs
Publication statusPublished - 01 Sep 2018

Keywords

  • finite element analysis
  • fracture toughness
  • high-strength carbon-fibre

ASJC Scopus subject areas

  • Aerospace Engineering

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