耦合运动非定常气动模型对飞机飞行特性仿真的影响

 在大振幅偏航滚转单自由度强迫振荡和耦合强迫振荡运动风洞试验的基础上,分别运用准定常气动力建模方法和非定常气动力建模方法,获取飞机的气动力模型;运用两种不同的气动力模型,对飞机的纵向正弦振荡机动飞行进行了仿真。结果表明,准定常模型在小迎角下的仿真结果与非定常模型的结果基本一致;在较大迎角时,准定常模型仿真结果趋于稳定,而非定常模型仿真结果使飞机进入横航向振荡飞行状态,这一现象与F-16XL的试飞结果类似,其主要原因是耦合运动的非定常模型与准定常模型所产生的阻尼特性不一致。这也表明,分析大迎角飞行特性时应考虑耦合运动下的非定常气动特性。     

一种固冲组合发动机进气道通气减阻方案的特性研究

提出了一种适用于整体式固体火箭冲压发动机的进气道通气减阻方案，并以矩形截面通气口高度、长度为变量进行了数值模拟实验，得到了其对阻力系数的影响规律。还给出了最佳通气方案的阻力系数随马赫数的变化规律，并与原始模型、进气口加堵盖方案进行了比较。最后结合一种具有常规气动布局的飞行器外形设计了模型，并对其进行了数值模拟研究和吹风实验，验证了方案的有效性和数值计算方法的可靠程度。     

Analysis of the Boeing 747-100 using CEASIOM

One of the requirements for the SimSAC project was to use existing aircraft to act as benchmarks for comparison with CEASIOM generated models. Within this paper, results are given for one of these examples, the Boeing 747-100. This aircraft was selected because a complete dataset exists in the open domain, which can be used to validate SimSAC generated data. The purpose of this paper is to both give confidence in, and to demonstrate the capabilities of, the CEASIOM environment when used for preliminary aircraft and control system design. CEASIOM is the result of the integration of a set of sophisticated tools by the European Union funded, Framework 6 SimSAC program. The first part of this paper presents a comparison of the aerodynamic results for each of the solvers available within CEASIOM together with data from the 747-100 model published by NASA. The resulting nonlinear model is then trimmed and analysed using the Flight Control System Designer Toolkit (FCSDT) module. In the final section of the paper a state-feedback controller is designed within CEASIOM in order to modify the longitudinal dynamics of the aircraft. The open and closed loop models are subsequently evaluated with selected failed aerodynamic surfaces and for the case of a single failed engine. Through these results, the CEASIOM software suite is shown to be able to generate excellent quality adaptive-fidelity aerodynamic data. This data is contained within a full nonlinear aircraft model to which linear analysis and control system design can be easily applied.     

黏附激励下空间目标惯性参数的辨识方法

针对黏附卫星会自然激励目标改变运动状态的现象，提出一种利用黏附激励进行空间非合作目标惯性参数的辨识方法。黏附前，利用主星对目标特征点的视觉测量，建立估计目标惯性参数与相对运动参数的滤波器，并估计目标的转动惯量比和质心；黏附后，主星直接利用该滤波器估计目标的新的质心速度，并基于动量守恒原理计算目标质量。该方法不仅充分利用黏附过程的自然激励，无需常规辨识必须的主动激励，而且激励前后算法一致，无需切换。数字仿真证实了算法的有效性。     

新一代飞机蒙皮绿色加工技术

<正>沿袭多年的传统飞机蒙皮化铣加工工艺,由于化学污染、耗电量大和消耗铝材无法回收等固有弊病而成为该行业的一项困扰。对于加工新一代铝锂合金蒙皮来说,化铣还需采取防燃防爆的特别措施,从而增加     

On the generation of flight dynamics aerodynamic tables by computational fluid dynamics

An approach for the generation of aerodynamic tables using computational fluid dynamics is discussed. For aircraft flight dynamics, forces and moments are often tabulated in multi-dimensional look-up tables, requiring a large number of calculations to fill the tables. A method to efficiently reduce the number of high-fidelity analyses is reviewed. The method uses a kriging-based surrogate model. Low-fidelity (computationally cheap) estimates are augmented with higher fidelity data. Data fusion combines the two datasets into one single database. The approach can also handle changes in aircraft geometry. Once constructed, the look-up tables can be used in real-time to fly the aircraft through the database. To demonstrate the capabilities of the framework presented, five test cases are considered. These include a transonic cruiser concept design, an unconventional configuration, two passenger jet aircraft, and a jet trainer aircraft. Investigations into the areas of flight handling qualities, stability and control characteristics and manoeuvring aircraft are made. To assess the accuracy of the simulations, numerical results are also compared with wind tunnel and flight test data.     

电子产品无铅焊接工艺和实施方法探讨

综述了国外无铅焊接技术规定、无铅焊料的开发及无铅焊料的种类、性能比较.由于铅对人体危害严重,法定所有的电子设备中禁止使用铅等有害物质.无铅焊接是大势所趋,航天电子产品只有顺应潮流,学习总结国内外先进的无铅焊接工艺,合理的选择焊料、印制板涂层/镀层,制定无铅焊接的工艺标准,才能保证航天电子产品无铅焊接的质量.     

碳纳米管在双基推进剂中的分散技术

为了改善双基推进剂的综合性能,拟将碳纳米管(CNTs)引入到双基药体系中,而其分散的均匀性可能影响添加效果,因此针对CNTs的分散方法进行了研究.首先将提纯处理后的CNTs经过高剪切力机械分散和超声波分散方法在溶剂中预分散,然后按0.25%～4%的添加量采用微胶囊分散工艺和溶剂法捏合工艺将CNTs分散到双基推进剂基体中...     

Generalized approach to resolution analysis in BSAR

Bistatic synthetic aperture radars (BSARs) have been the focus of increasing research activity over the last decade. The generalized ambiguity function (GAF) of bistatic SAR is introduced here. First, the GAF for BSAR is represented in the delay-Doppler domain, and is then expanded to the spatial (coordinates) domain. From the GAF, comprehensive knowledge regarding the resolution of BSAR can be extracted, including the range and azimuth resolutions, as well as the area of a resolution cell of BSAR. These general results are also applied to the performance analysis of several particular BSAR geometries, including the space-surface-BSAR (SS-BSAR) system, to demonstrate the potential ability of this newly introduced system.