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This paper has presented a technique for the determination of an optimal configuration of fuselage mounted piezoelectric actuators for active structural acoustic control of interior noise in aircraft. The technique has demonstrated much potential in preliminary experiments where actuators were configured to couple into the first principal component of the acoustically coupled fuselage vibration. In this test, average reductions of 6 dB at the error microphones and 4 dB at five auxiliary microphones were observed for a pure tone disturbance at the left forward engine pylon of a business jet. This disturbance was used to simulate an oscillating force due to engine unbalance.

This paper details the multidisciplinary design optimization (MDO) of a strut-braced wing aircraft and its benefits relative to the cantilever wing configuration. The multidisciplinary design team is subdivided into aerodynamics, structures, aeroelasticity and synthesis of the various disciplines. The aerodynamic analysis consists of simple models for induced drag, wave drag, parasite drag and interference drag. The interference drag model is based on detailed computational fluid dynamics (CFD) analyses of various wing-strut intersection flows. The wing structural weight is partially calculated using a newly developed wing bending material weight routine that accounts for the special nature of strut-braced wings. The remaining components of the aircraft weight are calculated using a combination of NASA’s Flight Optimization System (FLOPS) and Lockheed Martin Aeronautical System formulas.