Bi-objective optimization of pylon-engine-nacelle assembly: weight vs. tip clearance criterion

• Published in: Structural and multidisciplinary optimization Vol. 48; no. 3; pp. 637 - 652
• Main Authors: Bettebghor, Dimitri, Blondeau, Christophe, Toal, David, Eres, Hakki
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.09.2013; Springer Nature B.V
• Subjects: Aircraft power supplies; Airframes; Assembly; Computational Mathematics and Numerical Analysis; Computer simulation; Criteria; Design optimization; Dynamic response; Engine design; Engineering; Engineering Design; Impact loads; Industrial Application; Multiple objective analysis; Nacelles; Nonlinear dynamics; Nonlinear phenomena; Nonlinear response; Rotor dynamics; Simulation; Sizing; Theoretical and Applied Mechanics; Tip clearance; Weight; Equivalent static load case; Rotordynamics; Bi-objective optimization; Aircraft component design; Fan Blade Off simulation; Thermo-mechanical model
• DOI: 10.1007/s00158-013-0908-7
• ISSN: 1615-147X

A realistic application of advanced structural and multi-objective optimization for the design of a fully assembled aircraft powerplant installation is presented. As opposed to the classical design process of powerplant installation that does not consider the influence of pylon sizing over engine efficiency, we develop in the present a fully integrated approach where both pylon and compressor intercase are designed at once. The main objective is to consider the impact of weight over tip clearance performance criterion and see how these two objectives are antagonistic. In this work, we perform in the same design session tasks traditionally devoted to the airframe manufacturer and aero-engine manufacturer. The overall weight of the assembly is minimized with respect to Specific Fuel Consumption (SFC) criterion. One interesting aspect of the process is that SFC criterion is based on highly proprietary models and its simulation and call within an optimization process is made available through the development of a webservice. One major phenomenon to consider in both pylon and engine design is Fan Blade Off (FBO) event, i.e. the sudden release of a blade. This event causes high impact loads and must be considered carefully in the design. Such a simulation is not an easy task and several nonlinear phenomena must be addressed (e.g. rotordynamics), not to mention the integration of this nonlinear dynamic response in a static structural optimization process. This article describes how the design of the full assembly is performed taking into account both objectives. Such a problem lies in multi-objective optimization field and then we describe the method we use to solve such a problem. The simulation of an FBO post-impact rotor dynamics is also described and we end up with the final results that show the influence of pylon-engine weight sizing over SFC.