Multidisciplinary optimization of an aircraft wing/tip store configuration in the transonic regime

Abstract

In this research, a multidisciplinary optimization procedure is described to delay the occurrence of store-induced flutter of an aircraft wing/tip store configuration. A preliminary design procedure was developed to enhance the performance characteristics of an aircraft wing model in the transonic Mach number regime. A wing/tip store configuration with the store center of gravity (c.g.) located at the 50% aerodynamic tip chord was chosen for structural optimization. The aircraft wing structural weight was chosen as the objective function with constraints on natural frequency, stress and flutter. Automated Structural Optimization System and Computational Aeroelasticity Program-Transonic Small-Disturbance were the computational tools employed to perform the structural optimization and subsequent aeroelastic (mutual interaction between the aerodynamics and structural deformation) analysis in the transonic regime. This work showed that an improved store-induced flutter speed was obtained by increasing the separation between the first two natural frequencies of the wing structure. These results were compared with the results of those cases in which the flutter constraints were incorporated, along with the stress and frequency constraints, in the optimization problem. The addition of the flutter constraint resulted in a negligible increase in flutter speed when compared with the flutter speed obtained from optimization with only frequency and stress constraints.