Aircraft design for mission performance using nonlinear multiobjective optimization methods

SUMMARYA new technique which converts a constrained optimization problem to anunconstrained one where conflicting figures of merit may be simultaneously considered hasbeen combined with a complex mission analysis system. The method is compared withexisting single and multiobjective optimization methods. A primary benefit from this newmethod for multiobjective optimization is the elimination of separate optimizations for eachobjective, which is required by some optimization methods. A typical wide body transportaircraft is used for the comparative studies.INTRODUCTIONAircraft conceptual design is the process of determining an aircraft configurationwhich satisfies a set of mission requirements. Engineers within several diverse disciplinesincluding but not limited to mass properties, aerodynamics, propulsion, structures andeconomics perform iterative parametric evaluations until a design is developed.Convention limits each discipline to a subset of configuration parameters, subject to asubset of design constraints, and typically, each discipline has a different figure of merit.Advanced design methods have been built into synthesis systems such thatcommunication between disciplines is automated to decrease design time 1,2. Eachdiscipline may select its own set of design goals and constraints resulting in a set ofthumbprint and/or carpet plots from which a best design may be selected. In addition, theconceptual design problem has been demonstrated to be very amenable to the use of formalmathematical programming methods, and these algorithms have been implemented toquickly identify feasible designs 3,4,5.