Experimental investigation of the influence of adding nanotubes on Mode I interlaminar fracture toughness of laminated composites

ARTICLE INFORMATION ABSTRACT Original Research Paper Received 13 January 2016 Accepted 04 February 2016 Available Online 02 March 2016 In this research, the influence of adding carbon nanotubes on the tensile and the mode I interlaminar fracture of glass-fiber-epoxy laminated composite has been experimentally studied. For this purpose, the hybrid glass-fiber-epoxy-nanotube laminated composites which have 18 fiber-glass plain-weave layers were manufactured by hand lay-up method. The epoxy resin system is made of Epon828 resin with Epikure F205 as the curing agent. The multi-walled carbon nanotube (MWCNTs) modified with hydroxide (-COOH) is also dispersed into the epoxy system as a reinforcement in a 0%, 0.1%, 0.5% and 1% ratio in weight with respect to the matrix. In addition, the tensile nano-resin and hybrid nanocomposite specimen were produced. The results of the tensile test of nano-matrixes indicate that the maximum change in Young's modulus, ultimate strength and fracture toughness of the samples is in the 0.5% sample, with a 31.2%, 21.4% and 16.66% increase with respect to neat sample, respectively. Moreover, the results of the tensile test of hybrid nano-composites indicate that the maximum change in fracture toughness, ultimate strength and fracture strain and of the samples is in the 0.5% sample, with a 12.6%, 9.8% and 12.6% increase with respect to neat sample, respectively. The result of the mode I interlaminar fracture toughness test of hybrid nano-composites shows that the maximum change in value of the force (in force-displacement diagram) and value of the energy (of crack propagation in mode I interlaminar fracture), is in 0.5% sample, with a 24.4% and 24.15% increase respect to neat sample, respectively.