Abstract
The objective of this work is to enhance the mechanical properties of unidirectional [0](8) and quasi-isotropic [0/+/- 45/90](s) glass-fiber-reinforced composites by ultrasonically dispersing alumina-nanoparticles in epoxy matrix. The well dispersed alumina-nanoparticles in epoxy resin significantly improved the mechanical properties of alumina-nanocomposites. Results from fracture characterizations of the nano-hybridized unidirectional laminates with different off-axis angles showed high improvements in the interfacial bond strength between nanophased epoxy and glass fiber. Therefore, the flexural strength, modulus, and fracture toughness of quasi-isotropic laminate are significantly improved. Results from free vibration tests showed that the beam free length has high effects on the natural frequencies and the both have insignificant effect on the storage moduli of the composite laminates. For the investigated materials, the storage moduli correlated well (R-2 = 0.99962) with the flexural moduli. The damping ratios of the nano-hybridized quasi-isotropic and unidirectional laminates are improved by 62% and 60%, respectively. These improvements, which were achieved through conventional processing, are essentially for developing the structural components of automotive and aerospace industry. (C) 2014 Elsevier Ltd. All rights reserved.