1 PROBABILISTIC DESIGN OF AEROSPACE VEHCILES: COUPLING GLOBAL AND LOCAL REQUIREMENTS

This paper presents a probabilistic optimization methodology for conceptual design of aerospace vehicles that takes into account linkages between global and local design requirements. Multiple disciplinary analyses such as geometry, weights, structures, aerodynamics, trajectory, propulsion, thermal protection, operations and maintainability etc. are involved in the overall conceptual design. The global design considered in this paper optimizes the geometry for minimum weight while satisfying aerodynamic constraints. The local design illustrated here relates to structural sizing of vehicle components, e.g., liquid hydrogen tank. The optimization formulation includes probabilistic constraints, which are evaluated using the limit state-based reliability analysis methodology. The global and local designs are linked through probabilistic data flow relating to vehicle geometry and component weight, and the optimization at both levels is achieved through an iterative process