Stage-wise multidisciplinary design optimization for multi-stage solid launch vehicle

Because of the strong coupling of multi-disciplines and the complicated algorithm and the low design efficiency, the integral optimization design of solid launch vehicle is a difficult, but important problem. To solve this problem, the multidisciplinary models of a multi-stage solid launch vehicle, including geometry, mass, aerodynamic, propulsion and trajectory/guidance systems, were established. Then, the multi-stage solid launch vehicle was divided into several sub-stages which were connected by the continuous requirements of the flight states. Thus, the system-level and subsystem-level solution frameworks were constructed. Furthermore, two types of optimization processes, named parallel and serial methods, were presented to solve the multidisciplinary design optimization (MDO) problem where the objective function is to minimize the gross weight. The results show that via the stage-wise formulation, the number of iterations can be reduced and better results can be obtained,compared with the traditional multidisciplinary feasible (MDF) method, and thus we verify the feasibility and superiority of the proposed approach applied to MDO problems for multi-stage solid launch vehicles.