Development of nanomaterial reinforced multi functional composite structures

Within the scope of this study, enhance the impact energy absorption of aluminum-foam(core) sandwich composite structures and make electrically condutive to the core material, which is an insulator by itself, by using shear thickening fluid (STF), which is an smart material with nano-material additives, aimed at the development of multifunctional composite structures, which are becoming increasingly important especially in the aerospace industries. Total dimensions of sandwich structures of 50 x 50 x 21.4 mm were formed by using 7075 series aluminum with a thickness of 1.6 mm on the outer surfaces and XPS (Extruded polystyrene foam) with a thickness of 18 mm on the core material. 6 different channel designs were made on the core material, including vertical holes of 2, 4 and 6 mm diameters and horizontal channels of 2, 4 and 6 mm widths. These channels were filled with STF prepared 40% by weight silica powder dispersed in 200 g/mol polyethylene glycol (PEG) medium. Multi walled carbon nanotubes (CNT) were added to the STF solution prepared for the purpose of providing electrical conduction. Optimum STF + CNT content was determined by considering the rheological and electrical parameters. Sandwich structures were subjected to low velocity impact test at 5, 10 and 15 J energy levels. As a result of the impact test, the reaction forces formed at the base of the sample were examined. Then, the sandwich structure design, which gives the optimum result in terms of electrical conductivity and the impact energy absorption performance, is evaluated.