Static design and optimization of aircraft wing structures with composite materials

• Κύριος συγγραφέας: Ζάραγκας, Θωμάς
• Άλλοι συγγραφείς: Zaragkas, Thomas
• Γλώσσα: English
• Έκδοση: 2021
• Θέματα: Composite materials; Bonded joints; Stiffened panel; Optimization; Σύνθετα υλικά; Συνδέσεις με κόλλα; Ενισχυμένο κέλυφος; Βελτιστοποίηση

On this thesis, several aircraft wing components are designed for finding an improved geometry and material system using optimization algorithms. At first, the development of wing components will be studied and how composite materials contributed to that in the last decades. Because of this, the advantages, properties and applications of composite materials will be mentioned. However, special attention will be given to a specific type of composite material, the one with carbon matrix. Closing the first part of this thesis, which is the theoretical background, the classic laminate plate theory is being understood since it is used at the analysis to a great extent and a whole chapter refers to the optimization field for engineering and industry. Regarding the part of analysis, the structural part that surrounds the main wing frame, that is the stiffened skin or else stiffened panel will be examined thoroughly. Several modeling techniques with finite elements, such as equivalent plate will be surveyed as well as adhesive modeling technique will be developed. The glue bonded joints constitute a significant survey topic, since their wide use in aeronautics, so the next component that will be analyzed extensively is a bonded doubler that actually it is a conjunction between two plates, in which the second has smaller dimensions. It is used for reinforcement on damaged skin components or for antenna adhesion on the airplane fuselage. So, the connection between flange and web can be analyzed with this method, so that the optimum lamina stack sequence around the adhesive can be estimated. Finally, a very important design parameter is the damage tolerance. It’s the final and most significant piece of the process that is added to the total stiffened panel analysis and makes it complete. Specifically, the damage that will be investigated is an open hole that is used on the airframe and skin for many reasons, such as bolted joints, cut-outs and weight reduction. The optimum stack lay-up is found for minimizing the stress concentration factor around hole.