面向自顶向下设计的装配模型研究

装配模型是支持数字化产品设计和制造的重要基础。设计人员通过装配建模表达产品的功能形状和设计师的设计意图。本文针对自顶向下设计模式对装配模型的特殊要求 ,提出一种面向自顶向下设计的装配模型 ,支持产品设计过程中的多种设计活动。给出了模型的维护方法 ,为自顶向下的装配设计提供了安全的数据支持。该模型为产品装配的自顶向下设计提供了良好的模型基础。     

基于自顶向下设计模式的桥式起重机主梁设计

介绍了自顶向下的设计过程和实施方法，并以某型号桥式起重机主梁的自顶向下设计为实例，研究了以“顶层基本骨架”模型为核心的自顶向下设计过程，实现了该主梁的设计和装配。论述了基于自顶向下设计模式的优势和设计中需要注意的问题。     

基于Pro/E的中药粉碎设备自顶向下数字化装配建模设计

本文简要介绍了中药无压粉碎、搅拌、筛选设备的功能和创新概念设计,详细描述了设备自顶向下数字化装配建模的设计过程,并展示了设计的成果,即设备的数字化总装模型和设备主要组件的数字化装配模型。     

基于知识的导弹结构样机建模技术研究

导弹结构样机是对导弹结构完整性的数字化描述。基于CATIA设计平台进行了导弹结构样机建模技术研究,包括基于外形骨架模型的自顶向下装配技术、基于参数化设计的导弹结构资源库建库、导弹结构基于模型的定义等。将专业的结构设计知识融入到设计平台中,提高了数字化设计技术在导弹结构设计工作中的应用水平。     

物件排放桁架机械手自顶向下的三维数字化设计方法研究

以物件排放桁架机械手的设计为例,运用SolidWorks软件,介绍了自顶向下的三维数字化设计方法过程.自顶向下的设计方法符合工程实践中从概念到具体模型的设计思路,能够将复杂装配体的设计化整为零,便于团队并行设计,可极大提高产品设计效率和质量.     

基于SolidWorks的自顶向下装配与参数化技术

介绍了在SolidWorks中自顶向下的装配设计过程和实施方法,提出以“顶层基本骨架”作为自顶向下设计时信息传递的桥梁,并以具体实例实现了装配过程和参数化设计。     

SolidWorks自顶向下方法在机械设计中的应用

现代工业制造产品装配过程,设计人员通常使用SolidWorks软件进行零件设计和加工。文章主要通过对SolidWorks软件．TESolidWorks自顶向下装配设计等问题进行简单介绍,并系统地说明自顶向下装配设计步骤和装配参数化技术。     

基于关联技术的自顶向下设计技术的应用研究

针对自底向上的设计建模技术存在的不足和自顶向下的设计方法在实际应用中存在的问题，提出了基于关联的自项向下的设计建模实施技术，并对自项向下的设计技术的实施方法中产品、部件(子部件)、零件间的依附关系进行了研究。结合某集尘器挂架的设计建模对自顶向下设计建模技术实施中涉及的装配树的建立、产品级控制结构的建立、产品级控制结构的发布、相关的详细设计等关键技术进行了总结和探讨。     

基于特征的产品装配建模系统

分析了特征概念在装配领域的意义和作用。描述了表达产品自顶向下设计过程的装配模型的内容，建立了一个基于特征的产品装配模型，并在此基础上给出了系统的具体实现和应用实例。     

数字化总装车间智能物流配送系统的应用

航天器的装配技术是航天制造技术的重要组成部分,基于数字化制造模式下的柔性装配技术,是实现航天产品快速高效研制的有效途径。针对航天产品总装过程中要实现自动化、数字化装配的要求,设计了基于麦克纳姆轮视觉导航技术的物料配送系统,在调度管理系统路径规划下完成部件、成件和产品的转运、自动对接等任务。     

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.     

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。     

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....     

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.