Multiobjective optimization of a commercial transport aircraft for cost and weight

Abstract

This paper discusses the optimization of a small, medium-range transport aircraft to minimize direct operating cost (DOC), gross weight, and a combination of these two objectives. An effective method for cost optimization of aircraft is desired, especially in the commercial sector where many decisions are costdriven. In the past, many conceptual and preliminary design efforts have assumed a direct relationship between gross weight and cost. However, this relationship is not necessarily the case. The methodology used here for cost prediction incorporates several inputs, not just gross weight. The optimization algorithm CONMIN is used for minimization of the single-objective and multiobjective functions. The design variables are wing loading, thrust-to-weight ratio, aspect ratio, wing sweep, and wing taper ratio. Constraints are imposed on takeoff distance, cruise speed, rate of climb, landing distance, and absolute ceiling. Weighted objectives and a gaming theory are both used as approaches to the multiobjective problem. Results of the optimization studies are presented and discussed.