Detection of damage of epoxy composites using carbon nanotube network

A detailed experimental study is conducted to understand damage initiation and growth in epoxy particulate composites using a multi-wall carbon nanotube (MWCNTs) conductive network under two different loading conditions: (a) quasi-static shear and (b) fracture. Two different particulates (a) Cenospheres (aluminum silicate hollow spheres), and (b) carboxyl-terminated butadiene acrylonitrile copolymer (CTBN) rubber of three different volume fractions (10%, 20% and 30%) and mass fractions (10phr, 20phr and 30phr) respectively are used in thermoset epoxy resin composites. First, MWCNTs are well dispersed in an epoxy matrix using ultrasonication, and later the above particulates are added and shear-mixed into the solution to prepare composites. A v-notch rail shear specimen configuration for shear experiments, and single edge notch tension (SENT) configuration for fracture are considered in this experimental study. A four-point probe methodology along with high-resolution data acquisition is employed to capture electrical-resistance response of network changes associated with non-linear deformation, damage initiation and growth within composites under said loading conditions. It is identified from experiments that the electrical response associated with the above mechanisms is quite different with the addition of particulates compared to that of epoxy with no particulate. © The Society for Experimental Mechanics, Inc. 2013