飞机工装设计知识库系统的研究

飞机制造过程中采用大量的工装以保证飞机制造的准确度并提高效率,在知识工程基础上建立知识管理系统是提高设计制造效率的一种有效途径。在对飞机工装设计和制造知识分析提取的基础上,阐述飞机工装设计制造知识管理系统体系结构及工装知识库系统的构建。     

航空工艺装备计算机辅助设计与制造技术

飞机制造中，工艺装备的设计与制造技术的发展对促进飞机制造技术的进步，提高飞机质量是非常重要的。阐述了工艺装备计算机辅助设计与制造技术在飞机制造中所起的作用和效果，以期促进该技术在航空工装设计、制造和管理工作中的应用。     

机身数字化对接装配工装结构技术研究

针对飞机机身结构特点及其对接精度要求,基于数字化标准工装关键特性的装配协调技术,引入机身对接装配移动式生产线和安全防护理念,设计制造了一套数字化对接装配工装。该工装不仅可以实现前、中、后机身的精细对接,满足机身对接精度要求,而且提高了飞机机身对接装配质量稳定性和对接装配效率,缩短了工装的研制周期和生产准备周期,节省了工装的研制成本,同时为飞机部段级数字化工装的设计提供了一个范例。     

飞机装配型架模块化设计相关技术分析

随着我国社会经济的快速发展,科学技术水平的日益提高,我国制造业发展水平也日益凸出,其中,飞机制造水平已经取得了长足的发展。飞机装配型架作为飞机制造水平的关键指标,在整个飞机研制过程中起着相当重要的作用,其设计结构决定了工装制造的周期与费用,进而影响着飞机研制的成本和周期,同时也对产品装配的准确度与协调性起着决定性作用,最终影响飞机制造的整体质量。     

数字化标准工装在飞机工艺研制中的研究与应用

随着中航工业某分公司数字化研制水平的不断深入,数字化制造技术已经由点向面地逐渐推广到飞机的工艺研制中。数字化标准工装作为其中的一种协调方法,在很大程度上撼动和颠覆了传统模式的模拟量工艺协调方法,成为未来数字化制造与协调的重要依据。中航工业某分公司以飞机型号研制为牵引,逐渐开展了这方面的研究与实践工作。     

飞机舱门生产线方案设计与优化研究

以成飞民机公司的空客A320飞机登机门生产线为研究对象,运用数字化和互换性协调的原理和方法,结合成飞民机公司的实际情况,在原2D登机门生产线的基础上设计了新的技术方案。该方案包括设计零件工装、装配工装和互换性调试工装以及优化装配工艺。为了解决目前生产线中零件精度低、工装不可靠、产品误差大等问题,重新布局一条以3D数模和图纸为制造依据的登机门3D新生产线,以期为行业内其他型号飞机的舱门生产线设计提供可能的技术借鉴。     

外翼翼盒对接面装配协调的容差分析及工艺优化

随着飞机结构和工艺的发展,飞机制造的协调准确度要求越来越严格,因此利用数字化手段进行容差分析,实现工艺优化己成为必然趋势。通过对飞机部件装配的误差累计分析与容差优化理论进行研究,提出了基于软件仿真分析解决实际制造中尺寸工程问题的方法,并利用基准统一原则,对某机型外翼翼盒对接面的装配协调要求进行优化分析。结果表明,该理论与技术方法的应用改善了翼盒对接面的工程及工艺方案,提高了装配协调准确度分析的效率,具有一定的工程应用价值。     

空客大型飞机的柔性装配

大型飞机装配既是体现一个企业乃至国家制造技术水平的环节,也是缩短飞机制造周期、降低飞机制造成本的关键过程。除了利用先进的数字化和自动化技术之外,采用先进的柔性工装和夹具也是缩短周期、降低成本的重要手段。空客公司在A380、A400M和A350等大型飞机的装配中,通过采用     

飞机数字化柔性工装技术研究

中国工装设计制造水平低,已成为飞机快速研制及批量生产的瓶颈.分析了目前中国飞机装配中存在的问题,总结了国外飞机先进数字化柔性工装的研究及应用现状,综述了虚拟装配、柔性工装、数控钻铆、激光跟踪等数字化装配     

数字化制造企业中知识管理集成框架及关键技术研究

针对数字化制造企业中基于知识的设计和制造问题,提出了一个知识管理集成框架模型,并就制造企业中构建知识管理系统中的知识获取、知识建模和表示、知识推理、知识重用以及基于知识的推/拉辅助设计等技术进行了研究。最后,通过基于知识的典型飞机零件设计的具体实例,进一步说明了飞机制造企业中的知识管理集成框架的应用。     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

INTEGRAL EQUATION METHOD＇S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES

The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.     

Short-Term Relay Quality Prediction Algorithm Based on Long and Short-Term Memory

The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar...     

End-to-End Multiview Gesture Recognition for Autonomous Car Parking System

The use of hand gestures can be the most intuitive human-machine interaction medium.The early approaches for hand gesture recognition used device-based methods....     

Application of Feature Extraction through Convolution Neural Networks and SVM Classifier for Robust Grading of Apples

This paper proposes a novel grading method of apples,in an automated grading device that uses convolutional neural networks to extract the size,color,texture,an...     

分布动态载荷识别的抗噪处理

针对正交多项式频域法在用多种响应对矩形薄板进行载荷识别中抗噪性较差的问题,综合运用平均法、矩阵预处理和奇异值截断法等方法对之进行改善,并引入空间映射的思想,将该方法的应用范围拓展为复杂的模型.利用仿真算例,证实了该方法具有较好的抗噪性.     

基于MELTAC-N平台的核电厂安全级DCS环网研究与测试

针对工程实践中环网通讯相关问题的处理缺乏理论基础及国产化安全级DCS平台的开发缺乏成熟经验借鉴问题,对基于MELTAC-N平台核电厂安全级DCS环网的软硬件实现进行了研究。提出了安全级DCS环网双环网冗余设计、光切换开关设计等硬件设计方法,以及以RPR协议为基础,采用全数据收发策略的软件设计方法。在CPR1000安全级DCS平台上对安全级DCS环网的可靠性及实时性进行了评价,并进行了容错能力、响应时间及响应时间稳定性测试验证实验。结果表明,基于MELTAC-N平台安全级DCS环网软硬件设计具有较好的容错能力及响应时间稳定性。     

The laboratory simulation of abrasive wear

Abrasive wear has long been recognised as one of the most potentially serious tribological problems facing the operators of many types of plant and machinery; several industrial surveys have indicated that wear by abrasion can be responsible for more than 50% of unscheduled machine and plant stoppages. Locating the operating point of a tribological contact in an appropriate operational ‚map’︁ can provide a useful guide to the likely nature and origins of the surface degradation experienced in use, though care must be exercised in choosing the most suitable parameters for the axes of the plot. Laboratory testing of materials and simulations of machine contacts are carried out for a number of purposes; at one level for the very practical aims of ranking candidate materials or surface hardening treatments in order of their wear resistance, or in an attempt to predict wear lives under field conditions. More fundamentally, tests may be aimed at elucidating the essential physical mechanisms of surface damage and loss, with the longer term aim of building an analytical and predictive model of the wear process itself. In many cases, component surface damage is brought about by the ingress of hard, particulate matter into machine bearing or sealing clearances. These may be running dry although, more usually, a lubricant or service fluid is present at the interface. A number of standardised wear test geometries and procedures have been established for both two- and three-body wear situations, and these are briefly described. Although abrasive wear is often modelled as following an ‚Archard’︁ equation (i.e. a linear increase in material loss with both load and time, and an inverse dependence on specimen hardness) both industrial experience and laboratory tests of particularly lubricated contacts show that this is not always the case: increasing the hardness differential in an abrasively contaminated lubricated pair may not always reduce the rate of damage to the harder surface.     

ANGULAR DISTORTION ALLOWABLE VALUE AND ASSESS METHOD OF WELD ON COKE TOWER

A graph as the new engineering method for estimate the safety of bulging deformation of coke tower is proposed. Through stresses analysis of circumferential weld of coke tower and comparing the stresses produced by pressure with heat stress of steady state, residual stress, bending stress produced by both itself weight and wind loads, it showed that the stresses produced by pressure on the angle distortion are the main factor of equivalent stress of the combined stress. After comparing four kinds of stress controlling conditions, the relation to stress with depth of angular distortion, grade of curvature of angular distortion and half of region of angular distortion has been inferred. Graph of deformation allowable value of coke tower for different condition by angular distortion and half of region of angular distortion has been plotted. The five steps for its engineering use have been explained. The lighter the grade of curvature is, the larger of bulge allowance, may be, and the bigger of depth of angular distortion may pose too. For the coke tower with a popular structure of Dg 5 400 mm×28 mm, the result by graph is nearly more than the result of two formulas formed by other research, the error is less than 7.0%. But, the graph can be easily applied to different size of angular distortion.