EVOLUTIONARY ALGORITHMS FOR COUPLED MULTI-CRITERIA OPTIMISATION PROBLEMS IN AERONAUTICS

Abstract. During the past decade aerodynamic shape optimisation techniques based on evolutionary algorithms (EAs) have been extensively developed. These methods have proved to be very effective to find optimal geometries for single criterion problems. Nonetheless they have not seen wide spread application in the aeronautical industry because of the high computational cost involved as they require many more function evaluations than the traditional deterministic counterpart. In this paper the requirements, formulation and implementation of a framework for analysis and optimisation of multidisciplinary and multi—criteria coupled optimisation problems in aeronautics is described. The framework includes a GUI, a robust Hierarchical Asynchronous Parallel Evolutionary Algorithm (HAPEA) optimiser, several aeronautical design modules, game strategies, parallel computing and post—processing capabilities. The application of the method is illustrated on three representative test cases related to aircraft conceptual and detailed design; namely, a detailed wing section design, a conceptual aero—structural wing design and a 2-D two objective aircraft high lift system design. Results indicate the practicality and robustness of the method to find optimal shapes and trade—offs between the disciplinary analyses and to produce a set of non dominated solutions of an optimal Pareto front. The conclusion of this paper will underscore that the proper application of sound engineering judgment in conjunction with evolutionary techniques and parallel computing architectures can lead to optimal design solutions and significant computational savings when applied to real world problems. All solutions found herein are computed from scratch and no initial guess of the geometrical shape (airfoil or wing) is required. These results will be examined for practical applicability in 3D industrial environment and future methodologies for strongly coupled MDO problems using Navier—Stokes flow analysis solvers will be outlined.

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