An optimization strategy is proposed to deal with the aerodynamic/stealthy/structural multidisciplinary design optimization （MDO） issue of unmanned combat air vehicle （UCAV）. In applying the strategy, the MDO proc...An optimization strategy is proposed to deal with the aerodynamic/stealthy/structural multidisciplinary design optimization （MDO） issue of unmanned combat air vehicle （UCAV）. In applying the strategy, the MDO process is divided into two levels, i.e. system level optimization and subsystem level optimization. The system level optimization is to achieve optimized system objective （or multi-objective） through the adjustment of global external configuration design variables. The subsystem level optimization consists of the aerodynamic/stealthy integrated design and the structural optimization. The aerodynamic/stealthy integrated design aims at achieving the minimum aerodynamic drag coefficient under the constraint of stealthy requirement through the adjustment of local external configuration design variables. The structural optimization is to minimize the structural weight by adjusting the dimefisions of structural components. A flowchart to implement this strategy is presented. The MDO for a flying-wing configuration of UCAV is employed to illustrate the detailed process of the optimization. The results indicate that the overall process of the surrogate-based two-level optimization strategy can be implemented automatically, and quite reasonable results are obtained.展开更多
Three new control factors are presented for calculating the multipole mode number （MMN） efficiently and precisely. The effects of these control factors on the number of integral samples and the precision of multilev...Three new control factors are presented for calculating the multipole mode number （MMN） efficiently and precisely. The effects of these control factors on the number of integral samples and the precision of multilevel fast multipole algorithm （MLFMA） are investigated. A new approach based on control factors which is proven to be able to improve the computational efficiency and reduce the needed memory significantly as well as ensuring the proper precision. For three aircraft models,the improved MLFMA is employed to analyze their multi-frequency scattering characteristics. It is found that aircraft shape can influence radar cross section （RCS） in different frequency zones. Both the multi-frequency RCS reduction characteristics of shape stealth aircraft and the conventional aircraft with stealth design taken into account are investigated,and the results show that shape stealth exhibits significant RCS reduction in the resonance and high-frequency zones,and with a weaker influence in the Rayleigh zone. Compared with radar absorbing material （RAM）,shape stealth yields a wider multi-frequency RCS reduction. The above-mentioned results can be applied to stealth design for multiple frequencies or even for all frequencies.展开更多
文摘An optimization strategy is proposed to deal with the aerodynamic/stealthy/structural multidisciplinary design optimization （MDO） issue of unmanned combat air vehicle （UCAV）. In applying the strategy, the MDO process is divided into two levels, i.e. system level optimization and subsystem level optimization. The system level optimization is to achieve optimized system objective （or multi-objective） through the adjustment of global external configuration design variables. The subsystem level optimization consists of the aerodynamic/stealthy integrated design and the structural optimization. The aerodynamic/stealthy integrated design aims at achieving the minimum aerodynamic drag coefficient under the constraint of stealthy requirement through the adjustment of local external configuration design variables. The structural optimization is to minimize the structural weight by adjusting the dimefisions of structural components. A flowchart to implement this strategy is presented. The MDO for a flying-wing configuration of UCAV is employed to illustrate the detailed process of the optimization. The results indicate that the overall process of the surrogate-based two-level optimization strategy can be implemented automatically, and quite reasonable results are obtained.
基金National Basic Research Program of China (61320)
文摘Three new control factors are presented for calculating the multipole mode number （MMN） efficiently and precisely. The effects of these control factors on the number of integral samples and the precision of multilevel fast multipole algorithm （MLFMA） are investigated. A new approach based on control factors which is proven to be able to improve the computational efficiency and reduce the needed memory significantly as well as ensuring the proper precision. For three aircraft models,the improved MLFMA is employed to analyze their multi-frequency scattering characteristics. It is found that aircraft shape can influence radar cross section （RCS） in different frequency zones. Both the multi-frequency RCS reduction characteristics of shape stealth aircraft and the conventional aircraft with stealth design taken into account are investigated,and the results show that shape stealth exhibits significant RCS reduction in the resonance and high-frequency zones,and with a weaker influence in the Rayleigh zone. Compared with radar absorbing material （RAM）,shape stealth yields a wider multi-frequency RCS reduction. The above-mentioned results can be applied to stealth design for multiple frequencies or even for all frequencies.
