Steady State Thermal Analysis to Investigate Total Heat Flux in a Fiber Metal Laminate for Variable Thickness

Abstract

Fiber metal laminate (FML) belongs to metallic materials class consisting of layers of metal and fiber composite laminates which are bonded together. This permits the structure to behave as a very simple metal structure with affordable properties such as good resistance to corrosion, high strength-to-weight ratio, good resistance to fire, and better fatigue properties. For the last few decades, Fiber Metal Laminates (FML) have shown high performance as lightweight materials and accordingly, their increasing demand in the aircraft industry has provided a strong foundation for the development of refined fiber-laminated structures. As hybrid composites, these FMLs are a composition of fiber-reinforced material bonded with thin metal layers. The most common types of FMLs are CARALL (carbon-reinforced aluminum laminate), GLARE (glass-reinforced aluminum laminate), ARALL (aramid-reinforced aluminum laminate), and CentrAl, which is bounded by a GLARE core and layers of aluminum. These hybrid composites, which have two key constituents namely aluminum metals and fiber-reinforced laminate, offer numerous advantages such as resistance to fatigue failure and overcoming crack growth, mostly in aircraft applications.GLARE is composed of thin aluminum sheets that are bonded together using an epoxy adhesive film in which glass fibers are embedded. The presence of the epoxy layers requires attention to be given to moisture ingress, which can occur during the aircraft's service life. An important parameter that might influence the material properties is the service temperature. During the daytime, the ambient temperature changes from -40°C to 55°C. The in-service temperature of the airplane changes from -55°C to 70°C. Especially the increased or elevated temperatures could affect the material properties of the epoxy and thus the GLARE properties. Hence, this study mainly focuses on temperature influences on GLARE material when the laminate thickness is considered as a variable and total heat flux is calculated for the temperature differences.