Evaluating vibration assisted vacuum infusion processing of hexagonal boron nitride sheet modified carbon fabric/epoxy composites in terms of interlaminar shear strength and void content

The results of an investigation of the effect of voids on the interlaminar shear strength (ILSS) of carbon fabric/epoxy composites consolidated from fabric preforms containing hexagonal boron nitride sheets (h-BNSs) were presented. To produce the preforms, h-BNSs were first dissolved in ethanol through sonication and the solution obtained was then used for through-the-thickness impregnation of carbon fabrics. The composites with h-BNSs were produced by membrane added vacuum infusion process (MAVIP) with application of mechanical vibrations at various different low frequencies, including 10, 25 and 60 Hz. For the sake of property comparison, identical static samples were also produced. A facile thermogravimetric analysis (TGA) based methodology was utilized for composite fiber volume fraction and void content measurements. Analysis was carried out on specimen-by-specimen basis, and the findings obtained were correlated with the ILSS of the composites. It was determined that the composites produced at 10 Hz exhibited the lowest void content, whereas the highest one was obtained from the composites produced at 25 Hz. The highest fiber volume fraction, density, and ILSS values were obtained from the composites that were produced at 60 Hz. The findings obtained were discussed, placing particular emphasis on the interrelationships among ILSS, mechanical vibration frequency, and composite fiber volume fraction and void content. (C) 2016 Elsevier Ltd. All rights reserved.