Aircraft Fuselage Design Study

Abstract

The strong search for lightweight materials has become a trend in the aerospace industry. Aircraft manufacturers are responding to this trend and new aerospace materials are introduced to build lighter aircrafts. However material manufacturers, like Tata Steel, are unfamiliar with the determination of running loads and the behavior of materials in fuselage structures. Therefore an evaluation tool is needed for determining the running loads and evaluating the performance of new materials. This will give material manufacturers better insight in what properties and performance are specifically needed for materials in aircraft structures. The goal of this project is to develop an analytic design, analysis and evaluation tool for both metal and composite fuselage configurations in Visual Basic Application in order to gain insight into the structural performance of these material classes and to estimate the weight and required structural dimensions for both aluminum and composite fuselages. The fuselage geometry is setup parametrical and modeled as a simplified tube with variable crosssection without cut-outs and wing box, and it is divided in bays and skin panels. By modeling the aerodynamic-, gravity-, ground reaction forces and internal pressure a free body diagram and force/moment distribution is created for several flight and ground load cases, like 1G flight, lateral gust or landing load cases. The critical load cases are used for analysis. The running loads, like bending stress, longitudinal stress, circumferential stress and shear stress are calculated for the entire aircraft fuselage. A clear load pattern is created in order to evaluate the materials. The materials are evaluated for strength, stability and several other failure modes, like fatigue and crack growth. The skin panels are optimized for these evaluation methodologies and after doing so a minimum fuselage weight is obtained for conventional aircraft configurations. The Airbus A320 is taken as reference aircraft and the running loads and optimization results of the model are validated with this aircraft. The model proved to be valid and is therefore considered suitable to be used as an analysis and evaluation tool. The final stage of the project involved an initial assessment of aluminum and composite as structural material.