Hygrotermal effects evaluation using the iosipescu shear test for glare laminates

Abstract

Fiber-metal laminates (FML) composed of alternating layers of unidirectional fiber-reinforced plastic (FRP) laminae and aluminum-alloy sheets offer some superior mechanical properties, compared with either conventional laminates consisting of only FRP laminae or high-strength monolithic aluminum alloys. The environmental factors can limit the applications of composites by deteriorating the mechanical properties during service. Usually, polymeric matrix absorbs moisture when exposed to humid environments and metals are prone to surface corrosion. On the other hand, FML laminates presents more resistance of moisture when compared with their constituents. Evaluation of shear properties is particularly important in the design of mechanically fastened parts and components, which are subject to parallel and opposing loads. In this work, the shear behavior was studied for Glare laminates and its constituents in dry and wet conditions

Effects of surface pre-treatment and void content on GLARE laminate process characteristics

“…As the fraction of metal sheets in GLARE decreases, more shear load can be dissipated through the metal sheet-prepreg interfaces. This behavior is in congruence with earlier shear strength predictions of GLARE laminate (Botelho et al, 2008). It is interesting to note that both sets of ILSS data are closely grouped, which is a result of the fact that the reduced prepreg layer combined with low void content serve to increase the ILSS values of the GLARE laminate.…”

“…In particular, GLARE is being produced for the Airbus A380 (upper fuselage structures) at Stork Fokker in collaboration with Akzo and Alcoa as shown by Papanicolaou et al (2007), Botelho et al (2007) and Park et al (2010a,b). Botelho et al (2008) and Park et al (2010a,b) earlier presented that the applications for GLARE laminate in aeronautical structures has led to the demand for knowledge of a wide set of their properties and technological issues, including repair techniques. A critical challenge is to find a practical surface treatment method to obtain * Corresponding author.…”

“…Park). a durable GLARE structure because the bonding interface between aluminum sheets and glass/epoxy layers plays an important role in the load transfer of GLARE structures as shown by Botelho et al (2008) and Papanicolaou et al (2007). Currently, many aircraft manufacturers and airlines have specified the use of mechanical abrasions and/or chemical etches, which are often used to prepare the substrate surface prior to the application of an anodizing process (Ong et al, 1992;Davis and Bond, 1999;Critchlow et al, 2006;Liu et al, 2006a,b).…”

“…One of the most widely used fabrication processes for curing GLARE structures is an autoclaving process under relatively high pressure for consolidation (Botelho et al, 2008;Park et al, 2010a,b). The formation of voids can be controlled by process parameters such as cure temperature and consolidation pressure (i.e.…”

The effect of thermal cycles on the mechanical properties of fiber–metal laminates

“…Some papers compare the performance of FMLs and G/CFRP under hygrothermal conditioning on tensile/compression tests [12], interlaminar shear strength (ILSS) and Iosipescu testing [13,14] or vibration damping tests [15]. The procedure usually employs coupons conditioning in chambers at 80°C and 90% of relative humidity, according to ASTM D5229 standard [16], and a periodic evaluation of the mass gain of the coupons, up to a saturation point.…”