检索结果-南通市图书馆

Experimental and numerical studies on buckling and post-buckling behavior of T-stiffened variable stiffness panels

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of aeronautics 2024年第10期37卷 459-470页

作者： Yan HUANG Yahui zhang Bin KONG Jiefei GU zhe WANG Puhui CHEN State Key Laboratory of Mechanics and Control of Mechanical Structures Nanjing University of Aeronautics and AstronauticsNanjing 210016China AVIC Aviation Power Control System Research Institute Wuxi 214063China Chengdu Aircraft Design and Research Institute Aviation Industry Corporation of ChinaChengdu 610091China school of Mechanical Engineering Jiangnan UniversityWuxi 214122China school of aeronautic {2. and Engineering Beihang UniversityBeijing 100191China china National Key Laboratory of Strength and Structural Integrity Aircraft Strength Research Institute of ChinaXi’an 710065China

Currently,experimental research on variable stiffness design mainly focuses on *** ensure adaptability in practical application,it is imperative to conduct a systematic study on stiffened variable stiffness structures,including design,manufacture,experiment,and *** on the minimum curvature radius and process schemes,two types of T-stiffened panels were designed and *** compression tests have been carried out and the results indicate that the buckling load of variable stiffness specimens is increased by 2..0%,while the failure load is decreased by 19.6%.The influence mechanism of variable stiffness design on the buckling and failure behavior of T-stiffened panels was explicated by numerical *** primary reason for the reduced strength is the significantly increased load bearing ratio of *** experimental investigations of stiffened variable stiffness structures are very rare,this study can be considered a reference for future work.

关键词： Variable stiffness composite Buckling Post-buckling Finite element method Stiffened panels

Recognition of the major scattering sources on complex targets based on the high frequency radar cross section integrated calculation technique

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Shanghai university(English Edition) 2009年第4期13卷 316-321页

作者：黄敏杰吕明云黄俊武哲 school of aeronautic Beijing University of Aeronautics and Astronautics

Based on the high frequency （HF） integrated radar cross section （RCS） calculation approach, a technique of detecting major scattering source is developed by using an appropriate arithmetic for scattering distribution and scattering source detection. For the perfect adaptability to targets and the HF of the HF integrated RCS calculation platform, this technique is suitable to solve large complex targets and has lower requirement to the target modeling. A comparison with the result of 2.D radar imaging confirms the accuracy and reliability of this technique in recognition of the major scattering source on complex targets. This technique provides the foundation for rapid integrated evaluation of the scattering performance and 3-D scattering model reconstruction of large complex targets.

关键词： stealth technique radar cross section (RCS) scattering center scattering distribution map 2.dimension radar imaging

在线全文

学校读者我要写书评

暂无评论

不带速度测量的深空航天器网络编队控制

四川大学学报（工程科学版） 2011年第6期43卷 185-189页

作者：王楠张天伍徐洁琼河南工程学院计算机科学与工程系河南郑州451191 北京航空航天大学航空科学与工程学院北京100191

考虑处于深空中的航天器网络编队的位置和姿态控制。控制目标是使整个编队中的航天器在控制器的作用下达到期望的位置和姿态,同时航天器编队趋于期望的队形和期望的相对姿态。采用基于图论的方法设计控制器,得到的控制器仅仅要求相邻的... 详细信息

考虑处于深空中的航天器网络编队的位置和姿态控制。控制目标是使整个编队中的航天器在控制器的作用下达到期望的位置和姿态,同时航天器编队趋于期望的队形和期望的相对姿态。采用基于图论的方法设计控制器,得到的控制器仅仅要求相邻的航天器之间保持信息交换,从而,和已有的研究中要求设计航天器两两通信的控制器相比,减少了整个航天器网络内部航天器间的通信;另外,得到的控制器不要求相邻航天器的速度和加速度的测量,从而减少了测量所带来的累积误差。数值仿真结果验证了控制策略的有效性。

关键词：信息流图航天器网络队形控制姿态控制

Influence and determinative factors of ion-to-atom arrival ratio in unbalanced magnetron sputtering systems

在线全文

学校读者我要写书评

暂无评论

Journal of university of science and Technology {2. 2008年第6期15卷 775-781页

作者： Jun Zhou zhe wu Zhanhe {2. school of aeronautic {2. and Technology Beijing University of Aeronautics and Astronautics Beijing 100083 China

Low pressure sputtering with a controlled ratio of ion flux to deposited atom flux at the condensing surface is one of the main directions of development of magnetron sputtering methods. Unbalanced magnetron sputtering, by producing dense secondary plasma around the substrate, provides a high ion current density. The closed-field unbalanced magnetron sputtering system （CFUBMS） has been established as a versatile technique for high-rate deposition high-quality metal, alloy, and ceramic thin films. The＇key factor in the CFUBMS system is the ability to transport high ion currents to the substrate, which can enhance the formation of full dense coatings at relatively low value homologous temperature. The investigation shows that the energy of ions incidenced at the substrate and the ratio of the flux of these ions to the flux of condensing atoms are the fundamental parameters in determining the structure and properties of films produced by ion-assisted deposition processes. Increasing ion bombardment during deposition combined with increasing mobility of the condensing atoms favors the formation of a dense microstructure and a smooth surface.

关键词： magnetron sputtering closed-field unbalanced magnetron sputtering system (CFUBMS) ion-to-atom ratio unbalancedmagnetron sputtering

Optical and electrical properties of TiO_2.Au/TiO_2.multilayer coatings in large area deposition at room temperature

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2008年第5期27卷 457-462页

作者： ZHOU Jun wu zhe liu Zhanhe school of aeronautic {2. and Technology Beijing University of Aeronautics and Astronautics Beijing 100083 China

TiO2.Au/TiO2.multilayer thin films were deposited at polymer substrate at room temperature using dc （direct current） magnetron sputtering method. By varying the thickness of each layer, the optical and electrical properties of the TiOz/Au/TiO2.multilayer films can be tailored to suit different applications. The thickness and optical properties of the Au layer and the quality of the Au-dielectric interfaces are critical for the electrical and optical performance of the Au-dielectric multilayer thin films. At the thickness of 8 rim, the Au layer forms a continuous structure having the lowest resistivity and it must be thin for high transmittance. The multilayer stack can be optimized to have a sheet resistance of 6 D./sq. at a transmittance over 80% at 680 nm in wavelength. The peak transmittance shifts towards the long wavelength region when the thickness of the two TiO2.（upper and lower） layers increases. When the film thickness of the two TiO2.film is 45 nm, a high transmittance value is obtained for the entire visible light wavelength region.

关键词： magnetron sputtering multilayer films transparent conducting oxide optical and electrical properties

High mixing effectiveness lobed nozzles and mixing mechanisms

在线全文

学校读者我要写书评

暂无评论

science china(Technological sciences) 2015年第7期58卷 1218-1233页

作者： SHENG ZhiQiang CHEN ShiChun wu zhe HUANG PeiLin school of aeronautic {2. and Engineering Beijing University of Aeronautics and Astronautics

For a circular lobed nozzle with the exit plane displaced from the center body,adding a central plug at exit or replacing the nozzle with an alternating-lobe nozzle can improve the mixing *** this study,numerical investigations of jet mixing in the lobed nozzles with a central plug and alternating-lobe nozzles in pumping operation were *** effects of the central plugs with the wake ranging from attached to separated flow on the mixing were analyzed,along with the mechanism of improving the mixing performance in a"sword"alternating-lobe *** simulation results reveal that the large-scale mixing rate,which is dominated by streamwise vortices,is related to the intensity of the attainable heat and mass transfer in the streamwise *** effects of the streamwise vortices on the normal vortex ring are virtually a manifestation of the heat and mass transfer/mixing process of the streamwise *** simulation results also show that the central plug with the attached rear-flow performs better in improving the mixing effectiveness and pumping performance;on the contrary,if the rear-flow is separated,more pressure loss will be *** particular,a completely separated flow over the rear of the central plug will severely degrade the attainable heat and mass transfer in the streamwise *** the sword alternating-lobe nozzle,wider sword deep troughs help to increase the flux of the secondary stream around the core region and delay the confluence of the primary stream in the region between the deep and shallow ***,the mixing is improved in the middle and posterior *** to the lobed nozzle with a central plug,the improved sword alternating-lobe nozzle can achieve a higher mixing effectiveness with much less pressure loss,which is preferred in situations when the power loss of the engine is restricted.

关键词： jet mixing lobed nozzle mixing effectiveness streamwise vortices heat and mass transfer

A Knowledge-based and Extensible Aircraft Conceptual Design Environment

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of aeronautics 2011年第6期24卷 709-719页

作者： FENG Haocheng LUO Mingqiang liu Hu wu zhe school of aeronautic {2. and Engineering Beihang University Beijing 100191 China

Design knowledge and experience are the bases to carry out aircraft conceptual design tasks due to the high complexity and integration of the tasks during this phase. When carrying out the same task, different designers may need individual strategies to fulfill their own demands. A knowledge-based and extensible method in building aircraft conceptual design systems is studied considering the above requirements. Based on the theory, a knowledge-based aircraft conceptual design environment, called knowledge-based and extensible aircraft conceptual design environment （KEACDE） with open architecture, is built as to enable designers to wrap add-on extensions and make their own aircraft conceptual design systems. The architecture, characteristics and other design and development aspects of KEACDE are discussed. A civil airplane conceptual design system （CACDS） is achieved using KEACDE. Finally, a civil airplane design case is presented to demonstrate the usability and effectiveness of this v environment.

关键词： conceptual design knowledge engineering aircraft aerodynamics structural design weight estimation multidisciplinary design optimization

在线全文

学校读者我要写书评

暂无评论

一种多段机翼水面起降地效无人机气动特性

航空兵器 2024年第3期31卷 119-128页

作者：刘战合夏陆林马云鹏王菁张芦吴浩坤郑州航空工业管理学院航空宇航学院郑州450046 大连海事大学船舶与海洋工程学院辽宁大连116026 北京航空航天大学航空科学与工程学院北京100191 武汉理工大学航海与能源动力学院武汉430070

为改善水面起降性能和气动性能,基于船身式机身、多段机翼和T尾融合设计思路,提出并设计了一种新型仿生式多段机翼地效无人机方案,采用N-S方程和K-Ω-SST湍流模型,详细研究了该型无人机在不同状态下的压力云图、压力系数及升阻特性。仿... 详细信息

为改善水面起降性能和气动性能,基于船身式机身、多段机翼和T尾融合设计思路,提出并设计了一种新型仿生式多段机翼地效无人机方案,采用N-S方程和K-Ω-SST湍流模型,详细研究了该型无人机在不同状态下的压力云图、压力系数及升阻特性。仿真结果表明,地效作用随离水高度的增加而减小,离水高度与平均几何弦长之比(高度弦长比H/c)接近1时,地效作用较为显著,无人机在离水高度0.2.m时,升力系数、升阻比分别提升2..91%和40.37%,阻力系数降低15.2.%;对提出的多段机翼布局,地效飞行主要影响下表面压力系数和压力云图,下表面压力系数展向上由内向外正压增幅逐渐减小,弦向上前后缘附近压力系数较小,结合压力云图分析,地效对升力增幅的影响主要集中在中段和内段机翼下方区域;地效飞行可明显提高升力线斜率(H/c为1时提高了8.89%),迎角增加时升力系数增幅和阻力系数降幅均逐渐变大,升阻比增幅(H/c为1)在迎角2.后均达到2.%以上;通过验证机的多轮水面起降和有、无地效飞行试验,证明设计方案具有优秀的气动性能和飞行性能,可为水质检测、水面地效运输、搜救侦察等提供应用平台。

关键词：多段机翼水面起降气动性能无人机地面效应船身式

在线全文

学校读者我要写书评

暂无评论

变体飞行器结构关键技术及研究进展

电光与控制 2024年第1期31卷 1-13页

作者：张家应黄可武冠振王晨聂瑞北京航空航天大学强度与结构完整性全国重点实验室北京100000 北京航空航天大学航空科学与工程学院北京100000 南京航空航天大学航空学院南京210000 中国民用航空飞行学院航空工程学院四川广汉618000

变体飞行器由于可以根据飞行任务、飞行环境以及飞行状态等工况的改变主动地调整自身状态,从而可以实现在不同任务下都保持最佳性能。柔韧性和承载性良好的一体化柔韧蒙皮、大功率驱动器、轻量化高可靠性变形机构等智能柔性变形机翼技... 详细信息

变体飞行器由于可以根据飞行任务、飞行环境以及飞行状态等工况的改变主动地调整自身状态,从而可以实现在不同任务下都保持最佳性能。柔韧性和承载性良好的一体化柔韧蒙皮、大功率驱动器、轻量化高可靠性变形机构等智能柔性变形机翼技术是变体飞行器的重要支撑。为研究智能柔性变形机翼技术,在给出变体飞行器机翼主要变形方式的基础上,分析了变形机翼在变形蒙皮、驱动技术、变形机构等方面关键技术的研究重点和方法,并对其发展进行展望。

关键词：变体飞行器变弯度变展长变体翼尖局部变形技术跨速域变形