双刃组合式内R成形铣刀设计

正我公司与时代公司合作开发的1.7 m×1.7 m耐磨板热压模阴模上分布14 577个SR(5±0.05)mm球冠型面(见图1),根据现有设备和加工工艺,在龙门数控铣上用普通杆铣刀走三维程序铣削这些球冠型面,加工周期长达30天以上,并且铣削型面表面粗糙度远远达不到设计要求。为了提高加工效率和型面表面粗糙度质量,我公司专门研制出一种双刃组合式内R成形铣刀。1.设计原理创新设计的双刃组合式内R成形铣刀整体结构     

杆系柔性成形模具及其板成形加工关键技术

提出了一种可重构、低成本、高效率的板件成形加工模具———杆系柔性成形模,该装置可以快速重构各种形状的板件成形加工模具。详细地分析了杆系柔性成形模的结构及其重构方案,采用可更换的“变形冲压头”与离散杆配合,较好地构成模具成形面,保证板件有较好的成形精度;提出了一种新颖的板成形方法———模内压板与成形复合工艺,通过这种工艺方法与杆系柔性成形模相结合,可以抑制板件在成形过程中的受压屈曲与起皱,并可以减小成形板件的回弹量。该模具对复杂曲面板件的成形加工具有明显的优越性。     

HXD2型大功率机车合成闸瓦热压成型模具优化设计

为解决HXD2型大功率机车合成闸瓦热压成型模具结构不合理的问题,克服模芯翼板使用时易断裂的弊端,通过对模具热压成型机理进行工艺分析,找出问题产生的原因所在,对模型结构进行了优化设计,并运用有限元分析技术对改造方案进行了可靠性验证。方案实施后,满足了现场生产的需要,产品质量达到了工艺技术文件所规定的要求。     

基于型面联接改进模具的快速换模设计

在综述型面联接和模具的快速换模基础上,将型面联接的结构设计方法应用到改进冲压模具的快速换模的结构优化设计中。首先提出冲压模具的快速换模的结构改进设计的四个要求,再研究型面联接在冲压模具的凸模冲头在凸模固定板上的快速换模的结构优化设计的两个典型应用案例,并进行结构改进方案对比。研究结果不但能提高冲压模具的快速换模的效率和减轻操作者的劳动强度;而且能拓展型面联接在结构设计优化中的应用范围。     

车身冲模数控加工工艺设计研究

结合实例阐述了车身冲模翻边模上压料板制造工艺设计要点,并对模具零件的几何特征进行了分类;规划了上压料板数控程序编制方案,在此基础上,设计了上压料板结构面及型面的数控加工工艺;给出了其型面数控加工程序目录清单.结果表明:车身冲模零件的数控加TT艺适于采用基于结构特点、安装类型及加工性质的复合分类方法设计;所述实例经实践检验是可行的.     

热压罐成型框架式模具温度场分析

模具成型型面的温度均匀性对复合材料制件的成型精度具有重要影响。某大尺寸高平面度复合材料蜂窝夹层板构件利用热压罐工艺成型,模具为大型框架结构模具。文中采用有限元数值模拟方法,利用Simcenter12.0 软件对该大型框架结构模具热压罐成型工艺过程的温度场特性进行了模拟分析,模拟值与试验值误差小于10%,证明了模拟方法的准确性。模拟结果表明：成型固化工艺参数设置合理,模具型面温度均匀性较好,金属边框对模具的整体温度场影响较大;模具在热压罐内的位置在所设定的2.1 m 范围内沿长度方向移动对模具温度场的影响可以忽略。     

冲压模具零件的制造工艺

以级进冲裁凹模结构形状和技术要求为研究对象，介绍了级进凹模加工过程中遇到的问题和解决方法。着重阐述了级进冲裁凹模的加工工艺性及加工工艺方案，并详细说明了模具零件的加工工艺过程。     

异形型腔模具的冷挤压冲头工艺改进

图1所示为移动式插座模具型腔,是我厂使用的一模多腔塑压模中较典型的模具。该型腔形状异形,型面复杂并带有凸凹及圆弧连接。长期以来,采用热冲压及电脉冲加工     

级进模具镶块的单件加工

级进模具的镶块要求单件加工,通过改进加工工艺来保证单件加工的镶块在组装到底板上后型面、刃口完全一致,达到装配后的精度要求,并且要保证镶块的互换性。     

汽车覆盖件模具数控加工工艺

汽车覆盖件尤其是外板件,其形状、尺寸精度要求较高,而覆盖件模具尤其是高级汽车的覆盖件（外板件）尺寸公差、形状精度的要求更高,如果按照一般的加工工艺,难以保证模具的装配和型面精度。长城汽车精工模具技术有限公司是一家大型的模具公司。     

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.     

Limits of topographic measurement by the scanning tunnelling and atomic force microscopes

Parameters describing the topographic character of a surface (height, surface wavelength, slope and curvature) can be derived from equivalent sinusoidal profiles. The response of a surface-measuring instrument may be modelled in terms of instrument parameters such as stylus radius, and scanning range and resolution. The performance of the instrument may then be mapped as a zone in amplitude-wavelength (AW) space to show the sinusoidal profiles it is capable of measuring. In a first-order analysis the STM and AFM are considered as equivalent to contact-stylus instruments with a notional stylus radius equal to the tip radius plus the gap. Comparisons between different instruments and types of instrument are readily made by mapping in AW space. The error arising from convolution of the sinusoidal profile with that of the finite tip may be quantified and plotted as contours in AW space.