基于模型层次的参数化造型方法及实现

讨论了参数化造型方法在三维CAD系统中的应用,提出了一种基于模型层次的参数化造型方法,并在一种集成零件和装配的多层次三维CAD系统中加以实现和应用,给出了层次化参数定义的一种方法,使得参数化驱动的定义不仅可以引用模型自身的参数,而且也可以引用装配件上定义的参数,达到了跨模型、跨装配的参数化驱动。     

基于模型层次的参数化造型方法及实现

讨论了参数化造型方法在三维CAD系统中的应用,提出了一种基于模型层次的参数化造型方法,并在一种集成零件和装配的多层次三维CAD系统中加以实现和应用,给出了层次化参数定义的一种方法,使得参数化驱动的定义不仅可以引用模型自身的参数,而且也可以引用装配件上定义的参数,达到了跨模型、跨装配的参数化驱动。     

柴油机动平衡问题的多体系统动力学仿真

如何确定曲柄连杆机构中平衡块的几何形状、质量特性参数以及辅助平衡装置的方案和参数，是柴油机设计人员需要考虑的主要问题之一。将三维CAD软件Pro-E和多体系统（MBS）动力学仿真软件Workingmodel 3D结合起来，建立了单缸柴油机曲柄连杆机构的多体系统动力学分析模型，并用该模型仿真研究了S195柴油机曲柄连杆机构在额定转速下的动平衡问题，为柴油机动平衡问题的分析计算及平衡装置的设计提供了一种新的方法。     

内燃机曲轴系多体动力学研究

针对发动机的曲轴轴系系统,可以建立其三维的实体多体动力学模型用于研究,并且能够应用多体动力学的分析法对模型进行模拟分析,获取相关的载荷参数,为内燃机震动及噪音的产生及消除提供内容支持。本文简要概述了内燃机的曲轴以及多体动力学,并指出关于内燃曲轴系的多体动力学分析的模型建立以及边界条件,以更好地进行研究。     

三维CAD/CAE一体化的参数化动态有限元建模

提出了一种基于CAD参数化技术与CAD／CAE一体化技术的参数化动态有限元建模方法，该方法解决了三维实体有限元建模中几何模型的描述与驱动、参数联动、模型自动更新等一系列问题，为先进的参数化有限元分析与优化设计提供了关键技术基础；阐述了三维参数化动态有限元建模方法中的若干关键技术，包括具有典型意义的基于AutoCAD／MDT二次开发环境ObjectARX的CAD／CAE集成方法、复杂三维组合曲面网格全自动生成算法、复杂三维实体的四面体网格全自动生成算法、面向对象的有限元模型描述方法，以及有限元模型的参数驱动方法等；建立了一个三维参数化形状优化设计应用原型系统。     

基于实例的齿轮滚刀三维CAD模型参数化设计

针对齿轮滚刀的设计特点,通过建立一个实例齿轮滚刀的三维CAD模型,将模型中的特征控制属性值定义为参数,并用高级语言开发齿轮滚刀参数计算和与三维CAD软件联接的应用程序,在应用程序中,实现齿轮滚刀参数的自动计算与齿轮滚刀三维CAD模型的自动修改,以达到齿轮滚刀的三维CAD模型设计自动化.     

利用用户定义特征实现的冲压CAD/CAPP集成系统

提出了利用CAD系统的用户定义特征实现面向CAPP的特征设计的方法，在归纳定义常用冲压特征的基础上，建立了冲压特征信息模型，介绍了用Visual C 6．0在参数化三维特征CAD软件平台上开发的冲压CAPP系统，实际应用证明，用户定义特征是在商品化CAD系统中实现集成化CAD／CAPP系统的一种有效方法。     

基于实例的齿轮滚刀三维CAD模型设计

针对齿轮滚刀的设计特点,通过建立一个实例齿轮滚刀的三维CAD模型,将模型中的特征控制属性值定义为参数,并用高级语言开发齿轮滚刀参数计算和与三维CAD软件联接的应用程序。在应用程序中,实现齿轮滚刀参数的自动计算与齿轮滚刀三维CAD模型的自动修改,以达到齿轮滚刀的三维CAD模型设计自动化。     

气动CAD系统的研究开发

应用最新三维CAD技术，开发气动CAD系统，快速生成参数化模型，具有非常强大的可扩充性，便于实现CAD／CAM一体化。     

异构CAD系统零件库几何信息交换的研究

给出了实现异构CAD系统间零件库几何信息共享的一种新思路和有效途径 :分析主流通用三维CAD系统的共性 ,补充PLIB标准中零件几何信息模型的高层实体定义 ,进而考虑零件参数化信息和特征信息 ,建立基于特征的零件精确几何表达机制。在此基础上开发的接口实现了异构CAD系统间零件几何信息以及设计意图的共享。     

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.