基于Pro/E的机械零件特征模型库参数化设计

基于Pro/E作为支撑平台,以Pro/Toolkit作为核心技术开发的机械零件特征模型库的计算机模块系统,将机械零件的设计和三维实体建模融合起来,提高了零件的设计计算和绘图效率,实现了机械零件的快速造型和重构,系统具有良好的用户界面、可扩展性、很好的实用性和专业性.     

基于VBA的平面二次包络环面蜗轮副实体造型

介绍了采用VBA开发机械零件三维实体造型的实现机制和关键技术 ,通过平面二次包络环面蜗轮副实体造型程序实例 ,阐述了在VBA应用程序中三维实体造型的设计方法。     

基于VBA的平面二次包络环面蜗轮副实体造型

介绍了采用VBA开发机械零件三维实体造型的实现机制和关键技术，通过平面二次包络环面蜗轮副实体造型程序实例，阐述了在VBA应用程序中三维实体造型的设计方法。     

基于ARX开发环境的机械零件实体造型技术和实例

介绍了采用ＡＲＸ开发机械零件三维实体造型的实现机制和关键技术，通过阿基米德蜗杆齿廓的实体造型程序实例，阐述了在ＡＲＸ 应用程序中三维实体造型的设计方法     

CAXA三维电子图板中复杂三维零件模型的建立

CAXA三维电子图板是一个方便灵活的零件设计软件,它已经在机械、电子、航空航天、汽车、纺织、船舶、轻工、建筑等多个领域得到广泛的应用。CAXA三维电子图板通过先进方便的精确特征造型和强大的NURBS曲面造型相结合,创建机械零件的三维模型,并能用这个模型去自动创建二维图形。由于三维建模的直观、逼真、快捷及加工技术的不断改进,使工程设计从三维建模开始已成发展趋势。CAXA三维电子图板(EB3D)的三维造型功能为我们提供了生成三维实体的方法和手段。     

数控机床计算机辅助设计系统讲座 第六讲 零件绘图和优化设计(二)

叉架类机械零件包括叉类、架类、壳体类、轴承座等一些几何形状不规则的机械零件。这类零件结构复杂,设计难度大而周期长,且容易出错。因此迫切需要开发这类零件的计算机辅助设计软件,提高其设计速度和质量。 由于叉架类机械零件的几何形状复杂,用二维拼合的方法是不行的,用参数作图的方法也只适用于标准化程度较高、结构固定的零件设计。对五花八门的叉架类机械零件必须借助于三维实体造型技术而建立的三维几何模型,并通过消隐、变换和剖切才能生成零件工作图。 在工作站环境下的三维实体造型技术,已在第二、三讲中作了介绍,这里重点介绍在…     

三维实体造型方法对CFD计算影响的研究

三维实体建模是进行CFD(计算流体力学)计算的前提和基础.对同一实体,不同造型方法下生成的三维实体模型有着不同的几何信息和拓扑信息.本文从计算机图形学的角度,介绍了复杂几何实体的三维造型方法及其原理,并在此基础上,以离心泵蜗壳为例.分析了不同实体造型方法对CFD计算结果的影响.     

ARX和MFC混合编程实现三维实体造型

介绍了利用AutoCAD的二次开发工具ARX和MFC混合编程开发机械零件三维实体造型的实现机制和关键技术,通过实例阐述了在ARX程序中使用MFC进行三维实体造型的方法。     

基于UG NX的曲轴三维造型设计

介绍了曲轴的作用,分析了曲轴的三维造型设计的重要性,用UG的实体建模功能和特征建模功能对曲轴进行的三维建模。为曲轴的三维造型设计提供一种比较简便的方法。     

具有真实感的机械零件实体造型方法

简单介绍了ARX和OpenGL ,描述了基于MDT设计平台 ,在VisualC 编译环境下利用ARX和OpenGL进行具有真实感的机械零件的三维实体造型的一般过程 ,详细说明了利用ARX进行复杂零件的实体造型过程以及利用OpenGL对实体表面进行渲染的过程和方法。     

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.