Free Vibration and Buckling Analysis of Glass Fibers Reinforced Aluminium Laminated Epoxy (GLARE) Composites

Abstract

GLARE (glass-reinforced aluminium laminate) is a new variety of fiber metal laminates for advanced aerospace structural applications. It consists of thin aluminium sheets bonded together with unidirectional or biaxially reinforced adhesive prepreg of high-strength glass fibers. GLARE laminates offer a unique combination of properties such as outstanding fatigue resistance, high specific static properties, excellent impact resistance, good residual and blunt notch strength, flame resistance and corrosion properties, and ease of manufacture and repair. GLARE laminates can be tailored to suit a wide variety of applications by varying the fiber/resin system, the alloy type and thickness, stacking sequence, fiber orientation, surface pre-treatment technique, etc. Glass fibers reinforced polymer composites sandwiched in the GLARE material have been prepared by various manufacturing technologies and are widely used for various applications. Nowadays, it has been used in electronics, aviation and automobile application etc. Glass fibers have excellent properties like high strength, flexibility, stiffness and resistance to chemical harm. It may be in the form of rovings, chopped strands, yarns, fabrics and mats. Each type of glass fibers have unique properties and are used for various applications in the form of polymer composites. The present work deals with the theoretical and experimental analysis of GLARE composites. Finite element method in conjunction with Hamilton’s principle has been used to derive the equation of motion. The resonant frequencies have been determined for a GLARE composite with symmetric glass-epoxy composite [0/45/90/90/45/0]. Experiments are carried out to determine the resonant frequencies, using the sine sweep method. Though the theoretical and experimental values are fairly nearer, there is some difference. The experimental values are found to be less than the theoretical values. The reason may be due to the lack of perfect bonding between the layers, as have been assumed. Imperfect bonding increases the flexibility of the beam and hence there is a drop in the resonant frequencies. The experimentally determined buckling load is also less than the theoretical values, the reason may be due to imperfect bonding between layers and inaccurate estimation of the material properties.