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

Fiber metal laminate (FML) belongs to metallic materials class consisting of layers of metal and fiber composite laminates which bonded together. This permits the structure to behave as very simple metal structure with affordable properties such as good resistance to corrosion, high strength to weight ratio, good resistance to fire, better fatigue properties. For the last few decades, the Fiber Metal laminates (FML) which yields high performance as a light weight material and accordingly its increasing demand in aircraft industry have a strong basement towards the development of refined fiber laminated structures. As a hybrid composites these FML’s is a composition of fibers 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), CentrAl, that 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 resist fatigue failure and overcome the crack growth mostly in aircraft applications.Glare composed of thin aluminium sheets that are bonded together using an epoxy adhesive film in which glass fibers are embedded. The presence of the epoxy layers causes the attention has to be given to moisture ingress, which can occur during the aircraft service life.An important parameter that might influence the material properties is the service temperature. During the day time the ambient temperature changes from 40 o to 55 o C. The in-service temperature of the airplane changes from -55 o C to 70 o C. Especially the increased or elevated temperatures could affect the material properties of the epoxy and thus the glare properties. Hence this study mainly focused on temperature influences on glare material when the laminate thickness is considered as variable and total heat flux is calculated for the temperature differences.


Introduction 1.1 Glare and their material properties GLARE is a "Glass Laminate Aluminum
Reinforced Epoxy" comprises of number of thin layers of aluminum metal combined with glass fiber layers, "pre-preg", surrounded with a epoxy matrix. The pre-peg layers are aligned in various directions instead of uni-direction in order to support for stress conditions to be calculated. Moreover, the properties and the method of producing GLARE is very similar to aluminium metals. GLARE components are build using mostly classical material techniques. The advantages of GLARE over conventional aluminum metals are: [1][2][3][4][5].  Better damage tolerance  Good resistance to fire  more impact energy.
 Specific Weight is low  higher penetration resistance  Good Resistance to corrosion In 1987, Akzo Nobel got patent for first successful FML called GLARE, where Airbus A380 is the first commercial aircraft with this GLARE. During the period of material development, the major application on the Airbus A380, partners took part in production and development such as McDonnell Douglas Boeing, US Air Force, Bombardier. GLARE laminates comprise of alternative layers of high strength aluminum alloy sheets and unidirectional glass fiber reinforced prepreg's. ARALL with advanced glass fiber is the first improvement that is developed for aeronautical applications. [6][7][8][9][10]. On comparison the GLARE with ARALL has a major difference in combination with glass fibers rather than aramid fibers. This range of GLARE laminates have superior properties such as strength in the fibre direction and the specific stiffness, that are improved in high strength aluminum alloy metal layers being used. This enables weight reduction in the structural components designed for tension. It has a good adhesive property in between the glass fibers when compete with ARALL.

Method of Approach 2.1 Steady State Thermal Analysis using ANSYS:
A steady-state thermal analysis evaluates the influence of thermal loads under steady on the specific system or a desired component. Prior to conduct a transient thermal analysis, experts may perform steady-state thermal analysis, in order to generate initial values. Even for a transient thermal analysis at the end soon after analysis carried out, the transient effects will be reduced, and hence the last step will be the steady state thermal analysis. Therefore, this steady-state thermal analysis is used to determine the thermal properties such as thermal gradients, heat flux, temperature distribution and heat flow rates which do not change with respect to time. [11][12][13][14][15][16]. The following are the thermal loads: • Heat flow rates • Radiation • Convections • heat flow per unit area (Heat Flux) • heat flow per unit volume (Heat generation rates) • boundaries at Constant temperature There are three important tasks to conduct a steady state thermal analysis in ANSYS: • Creating Model geometry. • Application of Loads. • Obtaining results.

Creating Model Geometry
To create the geometrical model, the first step is to build a solid using lines, areas and volumes. predefined geometrical models are available in ANSYS library, such as rectangles, circles or thia can also done manually defining the nodes and elements for the geometry. The 2-D entities are known to be areas, and 3-D entities are known as volumes. geometry dimensions are followed by global coordinate system. The global coordinate system is Cartesian, X, Y, and Z axes by default. Instead, a different coordinate system can be selected as per the analysis.

Application of Loads (Thermal Loads)
Define the Type of analysis, apply the loads on the finite element model, set the step size options and solver, and solver for the solution. Analysis Type setup At this stage of analysis, the analysis type option to be given as: