An integrated optimization and surrogate analysis of large aircraft in conceptual design

The multidisciplinary design optimization (MDO) has the potential in large aircraft design. An integrated optimization method of large aircraft in conceptual phase is presented. The objective is the minimum stiffness of a beam-frame wing structure subject to aeroelastic, aerodynamic and stability constraints. The aeroelastic responses are calculated by commercial software MSC. Nastran, and the cruise stability is evaluated by the linear small-disturbance equations. A viscous-inviscid iteration method provided by commercial CFD solver MGAERO is used for computing the flow over the model. To reduce the computational burden and explore the entire design space, the evaluation of the responses in optimization is performed using Kriging model. The optimization method is validated by application to the wing of a complete aircraft. All the responses are computed in the trim condition with a fixed maximum takeoff weight. Genetic algorithm (GA) is utilized for global optimizations, and the optimal jig shape, the elastic axis positions and the stiffness distribution of the wing can be attained simultaneously, avoiding the iteration design.