• 제목/요약/키워드: aeronautics

검색결과 2,024건 처리시간 0.025초

Direct tracking of noncircular sources for multiple arrays via improved unscented particle filter method

  • Yang Qian;Xinlei Shi;Haowei Zeng;Mushtaq Ahmad
    • ETRI Journal
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    • 제45권3호
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    • pp.394-403
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    • 2023

  • Direct tracking problem of moving noncircular sources for multiple arrays is investigated in this study. Here, we propose an improved unscented particle filter (I-UPF) direct tracking method, which combines system proportional symmetry unscented particle filter and Markov Chain Monte Carlo (MCMC) algorithm. Noncircular sources can extend the dimension of sources matrix, and the direct tracking accuracy is improved. This method uses multiple arrays to receive sources. Firstly, set up a direct tracking model through consecutive time and Doppler information. Subsequently, based on the improved unscented particle filter algorithm, the proposed tracking model is to improve the direct tracking accuracy and reduce computational complexity. Simulation results show that the proposed improved unscented particle filter algorithm for noncircular sources has enhanced tracking accuracy than Markov Chain Monte Carlo unscented particle filter algorithm, Markov Chain Monte Carlo extended Kalman particle filter, and two-step tracking method.

  • https://doi.org/10.4218/etrij.2022-0001 인용 PDF

Optimization of hybrid composite plates using Tsai-Wu Criteria

  • Mehmet Hanifi Dogru;Ibrahim Gov;Eyup Yeter;Kursad Gov
    • Structural Engineering and Mechanics
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    • 제88권4호
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    • pp.369-377
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    • 2023

  • In this study, previously developed algorithm is used for Optimization of hybrid composite plates using Tsai-Wu criteria. For the stress-based Design Optimization problems, Von-Mises stress uses as design variable for isotropic materials. Maximum stress, maximum strain, Tsai Hill, and Tsai-Wu criteria are generally used to determine failure of composite materials. In this study, failure index value is used as design variable in the optimization algorithm and Tsai-Wu criteria is utilized to calculate this value. In the analyses, commonly used design domains according to different hybrid orientations are optimized and results are presented. When the optimization algorithm was applied, 50% material reduction was obtained without exceeding allowable failure index value.

  • https://doi.org/10.12989/sem.2023.88.4.369 인용

Design Study on a Variable Intake and a Variable Nozzle for Hypersonic Engines

  • Taguchi, Hideyuki;Futamura, Hisao;Shimodaira, Kazuo;Morimoto, Tetsuya;Kojima, Takayuki;Okai, Keiichi
    • 한국추진공학회:학술대회논문집
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    • 한국추진공학회 2004년도 제22회 춘계학술대회논문집
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    • pp.713-721
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    • 2004

  • Variable air intake and variable exhaust nozzle of hypersonic engines are designed and tested in this study. Dimensions for variable geometry air intake, ram combustor and variable geometry exhaust nozzle are defined based on the requirements of a pre-cooled turbojet engine. Hypersonic Ramjet Engine is designed as a scaled test bed for each component. Actuation forces of moving parts for variable intake and variable nozzle are reduced by balancing the other force in the opposite direction. A demonstrator engine which includes variable intake and variable nozzle is designed and the components are fabricated. Composite material with silicone carbide is applied for high temperature parts under oxidation environment such as leading edge of the variable intake and combustor liner. Internal cooling structure is adopted for both moving and static parts of the variable nozzle. Pressure recovery and mass capture ratio of the variable intake at Mach 5 is obtained by a hypersonic wind tunnel test. Flow characteristics of the variable nozzle are obtained by a low temperature flow test. Wall temperature and heat flux of the nozzle at Mach 3 is obtained by a firing test. As results, the intake and the nozzle are proved to be used at designed pressure and temperature environment.

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