Abstract:

In this article, a systematic and comprehensive investigation is made of the conceptual design for the use of a strut-braced wing (SBW) configuration in a transonic transport by means of multidisciplinary optimization design (MOD) carried out in the Multidisciplinary Analysis and Design (MAD) center of Virginia Polytechnic Institute (VPI). A suite of approximate analysis methods and tools of several disciplines are introduced and assembled into a complete conceptual level MOD code, which can realize the tightly coupled interaction between aerodynamics and structural weight, perform their balanced design and obtain their best synergism. LMAS, as an industry partner, which placed great emphasis on injection of their practical experiences into the MOD code, reviewed and validated the VPI MOD code. For a 325 passenger transport capable of flying a  13 890 km range at  Ma=0.85, numerous optimization design results reveal that the SBW configuration is 9.2%~17.4% lighter in take off gross weight(TOGW), burns 16.2%~19.3% less fuel, requires 21.5%~31.6% less engine power and costs 3.8%~7.2% less than its equivalent cantilever wing aircraft. Technology impact study and sensitivity of the constraints are analyzed and presented in this article. All the results clearly illustrate that the SBW configuration is one of the candidates of future transonic transports which can provide significant performance enhancement over existing transonic transport concept.

Key words: strut-braced wing, transonic transport, multidisciplinary optimization design, take off gross weight, sensitivity analysis