Multidisciplinary optimization of multi-lobe structures for hypersonic vehicles

Resumen

This work presents a comprehensive investigation into hypersonic cruise vehicles, aim- ing to significantly decrease the travel duration of long-distance journeys, such as the Madrid-Sydney route, to less than 4 hours. Achieving this goal necessitates the analysis of multiple engineering disciplines and the utilization of advanced modeling and design techniques. The culmination of these efforts will lead to the development of efficient configurations, representing future architectures capable of achieving low emissions while adhering to industry safety standards. The design of high-speed passenger ve- hicles is subject to very demanding conditions compared to traditional aircraft. This is due to the high loads and temperatures induced by the flows created in supersonic and hypersonic regimes. To solve these aspects, it is necessary to select suitable ma- terials and structural concepts that are adapted to the special characteristics of the vehicle. Multi-bubble architectures are an alternative for structures subjected to in- ternal pressures, mainly fuel tanks and passenger cabins. This concept uses several curved arches to form the volume, increasing the inertia and obtaining high mechan- ical performance. The main drawback is the difficulty in integrating them with the rest of the vehicle without incurring in excessive stress levels. For this reason is neces- sary to design additional schemes that are able to solve these deficiencies with respect to traditional fuselages. Structural optimization is a fundamental design tool in the field of aerospace engineering, commonly used in the design and production phases. In this type of industry, a small material saving can mean a clear decrease in the cost of the final prototype. Therefore, taking advantage of this tool for the design of hypersonic prototypes of is a key point. In this thesis, multi-bubble configurations ap- plied to hypersonic aircraft are studied. To size the components, several optimization technique are developed using different parametric models, obtaining complete designs that satisfy the imposed conditions.