适用于并行工程的基于约束的CAPP模型

 提出一种在计算机集成环境下编制工艺现程的方法,以“约束”的概念体现工艺学原则和实际生产环境信息。零件的被加工表面信息直接从集成数据库中获取。通过工艺数据库得到各被加工表面的各种可能的加工活动信息。对以这些加工活动为元素的集合施加位置关系约束,采用一定算法得到零件的多个可行工艺规程。该ＣＡＰＰ方法可在产品设计由粗到细的各个阶段实现,适于并行工程环境。     

An integrated systems engineering approach to aircraft design

The challenge in Aerospace Engineering, in the next two decades as set by Vision 2020, is to meet the targets of reduction of nitric oxide emission by 80%, carbon monoxide and carbon dioxide both by 50%, reduce noise by 50% and of course with reduced cost and improved safety. All this must be achieved with expected increase in capacity and demand. Such a challenge has to be in a background where the understanding of physics of flight has changed very little over the years and where industrial growth is driven primarily by cost rather than new technology.The way forward to meet the challenges is to introduce innovative technologies and develop an integrated, effective and efficient process for the life cycle design of aircraft, known as systems engineering (SE). SE is a holistic approach to a product that comprises several components. Customer specifications, conceptual design, risk analysis, functional analysis and architecture, physical architecture, design analysis and synthesis, and trade studies and optimisation, manufacturing, testing validation and verification, delivery, life cycle cost and management. Further, it involves interaction between traditional disciplines such as Aerodynamics, Structures and Flight Mechanics with people- and process-oriented disciplines such as Management, Manufacturing, and Technology Transfer.SE has become the state-of-the-art methodology for organising and managing aerospace production. However, like many well founded methodologies, it is more difficult to embody the core principles into formalised models and tools. The key contribution of the paper will be to review this formalisation and to present the very latest knowledge and technology that facilitates SE theory. Typically, research into SE provides a deeper understanding of the core principles and interactions, and helps one to appreciate the required technical architecture for fully exploiting it as a process, rather than a series of events.There are major issues as regards to systems approach to aircraft design and these include lack of basic scientific/practical models and tools for interfacing and integrating the components of SE and within a given component, for example, life cycle cost, basic models for linking the key drivers. The paper will review the current state of art in SE approach to aircraft design and identify some of the major challenges, the current state of the art and visions for the future. The review moves from an initial basis in traditional engineering design processes to consideration of costs and manufacturing in this integrated environment. Issues related to the implementation of integration in design at the detailed physics level are discussed in the case studies.     

层压复合材料连接接头设计及其在大飞机中的应用研究

 复合材料主承力接头的设计制造技术对拓宽复合材料在飞机结构上的应用范围,进一步减轻结构重量、提高疲劳性能和降低制造成本具有重要工程使用价值和发展应用前景。开展了平面环绕型层压板式复合材料承力接头的设计、分析与试验研究工作。提出了工程设计方案,通过理论推导,建立了环形接头危险部位的强度解析表达式并预测了具体接头设计的承载能力,同时完成了平面环绕型层压板复合材料接头的静力试验,试验结果与理论预测吻合良好。     

民机项目定费用设计

经济性对民机项目商业成功至关重要,概述了民机项目定费用设计的起源和基本概念,分别讲述研制费用的估算方法,设计经济性对单机成本的影响,设计经济性对运营成本的影响,总结出定费用设计是民机项目成本控制的关键。     

并行工程在商用飞机研制中的应用

介绍了并行工程的定义及国内外并行工程的应用现状,分析了商用飞机全寿命周期的费用。结合商用飞机研制特点,研究了基于成熟度定义的并行工程方法。通过并行工程的应用,缩短研制周期,降低研制费用。     

面向并行的CAPP集成系统的研制

自动工艺编排是CAD／CAPP／CAM集成系统各模块相互联系的重要纽带。工艺路线是整个工艺编排中最重要的部分。本文研究了基于并行工程的轴类回转体零件的CAPP系统的一些面向对象的设计方法，综合分析了影响工艺路线生成的因素，制定了合理的工艺规则，编排出科学的工艺路线，并与其它的功能模块实时进行信息的交互与反馈，有效地实现了并行工程，从而为CAD／CAPP／CAM系统的快速而有效地集成打下基础，并为CIMS系统的实用化提供新的技术支撑。     

开放式飞机总体设计环境的原型研究

 为综合集成飞机总体设计过程中所使用的各种设计分析工具以更大程度地发掘软件资源的技术价值、提高设计质量和设计效率,提出了采用开放式系统进行资源整合的方法。分析了飞机总体设计中软件应用所存在的问题及典型集成系统发展现状,定义了飞机总体设计中的模块、组件、子系统等功能实体单元及开放式系统架构的概念,并以此为基础设计了包含资源层、中间层、应用层和协同层4个层次的系统软件架构以及构建于网络之上的系统硬件架构体系。规划了系统集成与数据传输逻辑,提出了采用智能体进行飞机总体设计分析工具集成的途径,完成了包括组件自定义开发、方案设计和任务管理在内的各子系统构建逻辑并实现其正常运转。最后给出了基于系统开放式架构所形成的战斗飞机总体设计环境以说明系统集成的可行性及应用前景。     

航空发动机研制降低费用、缩短周期技术综述

概述了国外航空发动机研制费用和周期的情况;从高比例继承和多领域通用2方面,重点介绍了在国外航空发动机研制中降低费用、缩短周期所采用的成熟技术,同时介绍了优化设计技术和并行工程技术。     

Lessons learned using software-assisted systems engineering on large satellite development contracts

Over the years, the world's defense industries have become quite proficient at developing large, complex hardware and software systems. In recent years, the ubiquitous deployment of personal computers has changed the way we work. Additionally, took designed to facilitate systems engineering have recently matured enough to start having a major impact on many major systems development efforts. Finally, the government's faster-better-cheaper acquisition philosophy has started driving prime contractors to a concurrent engineering approach toward systems engineering. This confluence of experts is has had unexpected impacts on both the flexibility and rigor of requirements management processes. While the maturing requirements and design took hold great promise in maintaining requirements traceability throughout the design process, the widespread use of desktop computing systems has inadvertently lulled many experienced systems engineers into sloppy processes because it now appears to be a simple matter to make a requirements change in a softcopy of a requirements document. Without strong process and management support, requirements changes inevitably start being derived in a broad spectrum of incompatible took and formats. This author is currently participating in the design phase of a major classified government satellite development effort. As an integral member of an extremely experienced requirements management team (boasting over 150 years of combined experience in the defense industry), this author has had the opportunity to watch the team navigate straight into many of the systems engineering potholes created when talented engineers implement concurrent engineering using a variety of tools without a consistent process framework. This paper, therefore, specifically addresses process and implementation challenges that arose when establishing a software-assisted concurrent-engineering approach on a large satellite development contract.     

大型飞机自动化装配技术

 简述了大型飞机及其结构特点,通过比较人与机器两种装配系统的特性,及分析装配自动化水平与装配成本等诸因素的关系曲线,指出了自动化装配技术在保证大型飞机结构长寿命、高效率、低成本研制和生产等方面的意义;对国外大型飞机的装配自动化发展状况进行了综述,简要分析了国外发展的几种主要自动化装配系统,总结了国外大型飞机的自动化装配水平;对西方国家在大型飞机自动化装配中采用的先进的装配理念和方法,如决定性装配方法等进行了概述。最后针对国内自动化装配水平低的现状和大型飞机研制和生产的需求,提出了发展模块化结构的自动化装配系统、贯彻并行工程理念、实现面向制造和面向装配的设计等发展建议。     

Information systems requirements analysis and design: a balancedapproach

Over the last decade information engineering has become the methodology of choice for developing information systems. There are as many definitions of information engineering as there are practitioners of the techniques. This paper addresses information engineering from a practical perspective; it discusses how information engineering techniques can be applied to the real-life problem of identifying system requirements and satisfying those requirements with a computer-based information system. The paper also shows that information engineering, rather than being a new methodology, is made up of components of existing methodologies     

Flawed Metrics: Satellite Cost per Transponder and Cost per Day

In engineering design, metrics play a critical role in guiding design choices. It is therefore of prime importance that the metrics used to guide decision-making be the "right" metrics. This paper makes the case that two metrics used to guide communications satellites design, namely cost per operational day, and cost per transponder, are flawed under certain conditions in the sense that they result in design choices-increasingly longer lived satellites and larger payloads-that do not necessarily maximize the system's value. This paper advocates a value-centric mindset in system design, and proposes shifting the emphasis from cost to value analyses to guide design choices that maximize a system's value. Counter-examples are provided that challenge the traditional wisdom that longer lived or bigger satellites, being more cost effective on a per-day or per-transponder basis, are also more profitable or valuable. It is shown that while these metrics are useful guides for design choices in a supply-constrained market (in which a cost-centric mindset can prevail), they are flawed metrics on which to base decisions if the market is competitive, and in which the revenues from the system are not guaranteed to remain stable over time, through the impact of technology obsolescence, or overcapacity resulting in downward pressure on transponder lease prices. Finally, the case is made that the current market conditions require a value-centric mindset (as opposed to a cost-centric mindset) that views a spacecraft as a value-delivery artifact, and integrates considerations about the system's cost, its technical environment, and the market it is serving.     

航空发动机产品可制造性评估的应用研究

旨在为国内军品研制生产过程中应用可制造性评估提供必要参考,系统分析和总结了国外开展产品设计可制造性评估工作模式、方法和流程,重点描述了与英美等国外知名企业的合作和实践过程,特别是开展同步研发工作。结果表明:在传统串行设计开发模式中,只有完成上阶段工作,才能进入下阶段的工作及交换成套信息。而在可制造性评估中由于将制造工艺要求和质量要求提前引入产品设计过程,避免了传统模式中后期意见无法贯入设计图样和设计文件现象,证明其在缩短研制周期和降低成本方面是有帮助的。有必要将可制造性评估工作在国内航空发动机产品设计-制造产业链中推广应用。     

机翼结构布局优化的并行子空间方法

机翼内部构件的布局优劣在很大程度上影响着机翼结构质量,因此进行布局优化设计尤为重要。采用并行子空间方法求解机翼结构布局优化的问题,将机翼结构布局设计问题分为梁站位优化、桁条优化和厚度优化三个并行的子空间,设计变量在各自的子空间内单独优化;各子空间优化结束后,在系统级中协调三个子空间的设计变量,保持最小质量的子空间的优化变量不变;采用近似一维搜索的方法协调其他子空间的设计变量,然后进行变量迭代直至收敛。结果表明:该方法具有较高的优化效率,能够取得较好的优化结果,具有实际工程应用价值。     

一种高效的基于可靠性的多学科设计优化方法(英文)

Design for modem engineering system is becoming multidisciplinary and incorporates practical uncertainties; therefore, it is necessary to synthesize reliability analysis and the multidisciplinary design optimization （MDO） techniques for the design of complex engineering system. An advanced first order second moment method-based concurrent subspace optimization approach is proposed based on the comparison and analysis of the existing multidisciplinary optimization techniques and the reliability analysis methods. It is seen through a canard configuration optimization for a three-surface transport that the proposed method is computationally efficient and practical with the least modification to the current deterministic optimization process.     

What is systems engineering?

There are probably more definitions of “Systems Engineering” than there are AESS members. In its simplest form systems engineering is the design of the whole as opposed to the design of the parts. The vast number, complexity and diversity of elements can overwhelm and degrade system performance and reliability. Embedded processing and software can be both a boon and a bane. A systems engineer analyzes and optimizes an ensemble of elements that relate to the flow of energy, mass and communications into a design that performs the desired function. “Systems engineering” is used herein to cover a very broad spectrum of processes and controls to engineer a product at the many levels required to satisfy all aspects of the original requirement. Our definition is not intended to either include or exclude systems engineering and integration as used in the computer field. In any case, systems engineering is the application of solid engineering principles to design and develop a large enterprise within cost and schedule to satisfy the needs of the ultimate user. It involves conceptualization, design, development, test, implementation, approval/certification and operation (including human factors) of a system. In essence, systems engineering is a problem-solving discipline for the modern world     

飞机制造大型工装布局设计方法研究与实现

 飞机制造大型工装是保证飞机产品协调互换和几何参数的重要工艺装备,其研制工作量大,周期要求越来越短。目前,中国航空制造企业大型工装设计和制造并行的需求十分迫切,且亟需计算机辅助概念设计工具的支持。为此,对飞机制造大型工装的布局问题进行研究,引入逻辑构件对飞机制造大型工装进行抽象建模,提出了一种依据布局约束要求分级演进求解的布局设计算法,即依次通过定位点级、元件级和工装级骨架轴位域的演进求解获取骨架元件的合理位置,并结合人机域的求解进行工装布局设计。开发了相关布局设计工具,在某型号飞机后机身装配型架设计中应用验证,大大减少了设计迭代和返修率。     

Navier–Stokes solvers in European aircraft design

The paper gives a broad perspective of the progress made during the last 10 years in solving the Navier–Stokes equations and traces how this simulation technique went from being a specialized research topic to a practical engineering tool that design engineers use on a routine basis.

The scope is limited to Navier–Stokes solvers applied to industrial design of airframes with attention focused particularly on developments in Europe. An overview of the different Navier–Stokes codes used in Europe is given, and on-going developments are outlined.

The current state of progress is illustrated by computed steady and unsteady solutions to industrial problems, ranging from airfoil characteristics, flow around an isolated wing, to full aircraft configurations.

A discussion on the future industrial design environment is given, and developments in Europe towards a more integrated design approach with underlying concepts like ‘concurrent engineering (CE)’ and the ‘virtual product (VP)’ are summarized. The paper concludes with a discussion on future challenging applications.     

产品绿色设计研究现状及展望--一般理论及方法

综述了绿色设计的一般理论、方法和应用技术,介绍了公理化、模块化、质量功能配置等方法在绿色设计范畴内的应用,指出绿色设计必须与现有设计方法和并行工程有效融合,才能真正为设计者掌握和利用,发挥应有的作用。     

Variable-fidelity optimization with design space reduction

Advanced engineering systems, like aircraft, are defined by tens or even hundreds of design variables. Building an accurate surrogate model for use in such high-dimensional optimization problems is a difficult task owing to the curse of dimensionality. This paper presents a new algorithm to reduce the size of a design space to a smaller region of interest allowing a more accurate surrogate model to be generated. The framework requires a set of models of different physical or numerical fidelities. The low-fidelity (LF) model provides physics-based approximation of the high-fidelity (HF) model at a fraction of the computational cost. It is also instrumental in identifying the small region of interest in the design space that encloses the high-fidelity optimum. A surrogate model is then constructed to match the low-fidelity model to the high-fidelity model in the identified region of interest. The optimization process is managed by an update strategy to prevent convergence to false optima. The algorithm is applied on mathematical problems and a two-dimen-sional aerodynamic shape optimization problem in a variable-fidelity context. Results obtained are in excellent agreement with high-fidelity results, even with lower-fidelity flow solvers, while showing up to 39% time savings.