类乘波体飞行器的气动力工程计算

为估算高超声速类乘波体飞行器的纵向气动力,以三角形面元逼近飞行器外形,根据飞行器迎/背风面情况分别采用达黑姆-巴克法、普朗特-迈耶耳法、切锥法和膨胀波方法计算无粘气动力;通过经验公式估算粘性阻力,并考虑飞行器主要部件之间的气动干扰情况,计算了翼片之间、翼身之间的气动干扰因子,得到整个飞行器的气动力。为验证该方法,以某飞行器为例进行了计算,计算结果与CFD吻合。     

Human-computer interaction in aeronautics: a cognitive engineering perspective

This article presents issues and perspectives that are currently emerging from the evolution of new technology integration in aircraft cockpits. It advocates the need for cognitive engineers and human-computer interaction specialists to rationalize emerging practice in aviation, to better understand the current socio-technical evolution and to contribute in the human-centered design of the next generation aircraft. It also introduces six articles that show these trends and introduce some controversial discussions on various alternative solutions.     

利用导流板降低流场对光传输影响的试验研究

在一座小型跨超声速风洞上采用夏克-哈特曼波前传感器进行了Ma=3试验段流场对光传输特性影响的试验研究。空风洞流场的测试结果表明,由于试验段壁面湍流边界层中气流脉动与流场密度变化的影响,光波前会发生畸变。为了降低湍流边界层流场对光传输的影响,在风洞试验段单侧壁板上安装导流板进行了试验。测试数据表明,光波前畸变量的PV均值和RMS均值分别由3.5λ和0.73λ降低到了1.09λ和0.22λ,而且光波前畸变量的波动幅度也大为降低。初步研究结果说明,采用加装导流板等措施可以显著降低风洞流场对光传输的影响,有利于提高风洞试验时流场显示与测量结果的可靠性和有效性。     

Review of aerospace engineering cost modelling: The genetic causal approach

The primary intention of this paper is to review the current state of the art in engineering cost modelling as applied to aerospace. This is a topic of current interest and in addressing the literature, the presented work also sets out some of the recognised definitions of cost that relate to the engineering domain. The paper does not attempt to address the higher-level financial sector but rather focuses on the costing issues directly relevant to the engineering process, primarily those of design and manufacture. This is of more contemporary interest as there is now a shift towards the analysis of the influence of cost, as defined in more engineering related terms; in an attempt to link into integrated product and process development (IPPD) within a concurrent engineering environment. Consequently, the cost definitions are reviewed in the context of the nature of cost as applicable to the engineering process stages: from bidding through to design, to manufacture, to procurement and ultimately, to operation. The linkage and integration of design and manufacture is addressed in some detail. This leads naturally to the concept of engineers influencing and controlling cost within their own domain rather than trusting this to financers who have little control over the cause of cost. In terms of influence, the engineer creates the potential for cost and in a concurrent environment this requires models that integrate cost into the decision making process.     

一种实用的风力机叶片气动设计方法研究

提出了水平轴风力机叶片的优化设计模型,该模型以风轮平均年能量输出最大为设计目标,并将风速的概率分布考虑进来。为了获得较好的优化结果,首先采用PROPID程序对叶片进行反设计,获得较好性能的叶片几何,在此基础上,运用遗传算法进行搜索寻优,这样不仅减小了搜索的范围,也降低了搜索的时间。对叶片面积附加约束,以获得符合实际的叶片,采用5阶贝塞尔函数在设计点之间进行插值,以获得光滑的几何外形。利用该方法优化设计了600kW风力机叶片。与已有叶片相比,优化结果显示了明显的优越性,验证了该优化方法的有效性和实用性。     

On a plastic instability criterion for ultra-large radial-axial ring rolling process with four guide rolls

A dynamic mechanical model is proposed to describe the complexing actions of all the rolls on the ring during the ultra-large radial-axial ring rolling(RARR) process with four guide rolls. Based on the model, the calculation models for bending moment and normal stress at any section of the ring are deduced by force method. If the maximum section bending normal stress exceeds the yield stress of the ring materials, the ring will be distorted thus leading to the instability of the RARR process. Ac...     

Individual aircraft life monitoring: An engineering approach for fatigue damage evaluation

Individual aircraft life monitoring is required to ensure safety and economy of aircraft structure, and fatigue damage evaluation based on collected operational data of aircraft is an integral part of it. To improve the accuracy and facilitate the application, this paper proposes an engineering approach to evaluate fatigue damage and predict fatigue life for critical structures in fatigue monitoring. In this approach, traditional nominal stress method is applied to back calculate the S-N curve parameters of the realistic structure details based on full-scale fatigue test data. Then the S-N curve and Miner’s rule are adopted in damage estimation and fatigue life analysis for critical locations under individual load spectra. The relationship between relative small crack length and fatigue life can also be predicted with this approach. Specimens of 7B04-T74 aluminum alloy and TA15M titanium alloy are fatigue tested under two types of load spectra, and there is a good agreement between the experimental results and analysis results. Furthermore, the issue concerning scatter factor in individual aircraft damage estimation is also discussed.     

中国企业为何无缘全球品牌百强榜

文章在介绍全球品牌百强排行榜由来的基础上，通过解读Interbrand的品牌评价方法，对中国企业品牌目前难以上榜的原因进行了分析，认为中国企业应在发挥成本优势的同时，注重丰富品牌内涵，加强品牌营销和管理，踏实发展，避免浮躁，同时有关部门应对“中国制造”的品牌加以维护和扶持。假以时日，国产品牌定能进入世界顶尖品牌行列。     

The C-17 multifunction display: a building block for avionicsystems

The multifunction display (MFD) developed for use as the primary cockpit display system on the US Air Force C-17A military air transport is described. The 6-in by 6-in color cathode ray tube (CRT) display features a self-contained 1750 processor and vector generator capable of processing MIL-STD-1553B aircraft data and raster video into any of 10 formats as selected by the pilot or copilot. The MFD can display stroke, raster, or hybrid formats in 16 colors. Raster images are driven by sensor inputs with an RS-170 or RS-343 interface. The CRT uses a taut mask delta gun design and provides the best available brightness and line-width performance. The display features small size, low weight, low power, standard interface, and adaptable software. Reconfigurability in the aircraft is enhanced by using four identical cockpit displays     

Concurrent engineering in practice for small and medium enterprises: Findings from research and industrial pilot cases

While large companies are already actively pursuing the adoption of CE principles within their business processes, there is a need for supporting Small and Medium Enterprises to evolve their organizational and cultural schemes, as well as their technological and methodological approaches towards CE. The paper outlines the approach that has been undertaken. Furthermore, it describes a Software System for the support of SMEs in the introduction of CE by self-assessment, case presentation, and tool selection. Research results for the system's application are given.     

Remaining useful life prediction for engineering systems under dynamic operational conditions: A semi-Markov decision process-based approach

For critical engineering systems such as aircraft and aerospace vehicles, accurate Remaining Useful Life(RUL) prediction not only means cost saving, but more importantly, is of great significance in ensuring system reliability and preventing disaster. RUL is affected not only by a system's intrinsic deterioration, but also by the operational conditions under which the system is operating. This paper proposes an RUL prediction approach to estimate the mean RUL of a continuously degrading system under dynamic operational conditions and subjected to condition monitoring at short equi-distant intervals. The dynamic nature of the operational conditions is described by a discrete-time Markov chain, and their influences on the degradation signal are quantified by degradation rates and signal jumps in the degradation model. The uniqueness of our proposed approach is formulating the RUL prediction problem in a semi-Markov decision process framework, by which the system mean RUL can be obtained through the solution to a limited number of equations. To extend the use of our proposed approach in real applications, different failure standards according to different operational conditions are also considered. The application and effectiveness of this approach are illustrated by a turbofan engine dataset and a comparison with existing results for the same dataset.     

The J-MASS Marketplace: a new way for DoD to do business

It is current DoD policy to use commercial off-the-shelf software whenever it meets DoD requirements. The application of this policy to modeling and simulation has resulted in the concept of “The Joint Modeling and Simulation System (J-MASS) Marketplace.” J-MASS is designed as an Open Systems Architecture with the capability for the Simulation Support Environment (SSE) to be expanded by the addition of site specific software. In the “J-MASS Marketplace” industry will build commercial tools to work with J-MASS and individual organizations will license what they need for their particular site. The J-MASS SSE is a framework or backplane into which everything else plugs. A J-MASS product release would have the core capabilities, but the unique needs of various organizations would be satisfied by industry. This paper addresses how the J-MASS Marketplace could work and how compliance can be defined. It will outline opportunities for industry in both building software for the Marketplace and in defining the Marketplace concept     

CFD评估框架的进展及其最佳实践: QNET-CFD知识库

QNET—CFD是欧盟R＆D项目开发的一个主题网络，该网络讨论了计算流体力学（CFD）供工业应用应具有的品质和可信度，其主要目的是以系统和质量控制的方式收集CFD和实验数据，建立两者相容的知识库（KB），以此为基础，支持对CFD进行指导和评估。QNET—CFD围绕覆盖下述工业部门的6个主题（TA）组成：外流空气动力学；燃烧和传热；化学过程、热水力学和核安全：土木建筑和HVAC；环境；涡轮机内流。其主要成果是建立了具有面向用户界面及丰富的实验和CFD数据的知识库，这些数据来自于大量实验数据，分为53种应用挑战（AC）和43种基本流动状态（UFR）。除对上述6个主题领域中每一个的科学发展动态给出述评外，KB还包含了对大多数应用挑战如何利用CFD的最实际的建议，这被视为QNET—CFD最有意义的贡献，CFD的可信度和质量水平将因此得以进一步提高。     

从计划到规划：宏观经济管理手段的逻辑建构

通过对计划和规划概念上的比较分析,对市场经济条件下规划存在的必要性进行了探讨,并给予了肯定回答.在市场经济条件下规划具有经济宪章、促进经济社会协调发展、遏制政府失灵、构建经济伦理四个方面的作用,从而为规划作为宏观管理的重要手段建立了一个有解释力的逻辑框架.     

信息服务软件开发设计

本文介绍了一种准网络远程终端结构的设计实现,该结构的系统用于新闻信息发布,情报检索等应用领域,文中详细介绍系统的结构、性能、特征、具体实现方法和关键技术措施。     

The future of military radar: a perspective

This paper describes a perspective of military radar development. The foreseen configuration of radar systems in the first part of the 21 ^st century is proposed. The avenues of radar evolution and the expected occurrence of technological breakthrough are discussed