Intralaminar fracture toughness characterisation of woven composite laminates. Part II: Experimental characterisation

The tensile intralaminar fracture toughness of the carbon/epoxy 5HS-RTM6 woven composite material has been experimentally characterised, using the doubly-tapered compact tension (2TCT) specimen. This specimen geometry was found to achieve lower values for the failure indices described in the first part of the article. Two different configurations of the material were considered: one with the warp direction of the material parallel to the direction of the applied load and the other with the warp direction of the material perpendicular to the direction of the applied load. The obtained values for the mode I intralaminar fracture toughness were similar for both configurations. Although some tow splitting took place in the second configuration, from the analysis of the images obtained by DIC, X-ray and C-scan it was concluded that the effect and presence of other damage mechanisms different to mode I intralaminar crack opening was negligible. Consequently, the experimental values obtained were reliable and the 2TCT specimen was useful for its purpose.