新型盘类瓷器底部磨削机床设计

为了平整盘类瓷器底部,专门研制了一种新型自动盘类瓷器底部磨削机床,整个磨削过程采用砂带磨削并可实现自动化控制,利用对射传感器感应托盘中瓷器的存在,压磨板动作及瓷器进出磨削工位采用气动系统实现,磨削高度由机架下部升降机调整。模态分析结果展示磨底机升降装置座及升降体固有频率远超出磨底机工作频率,不会共振。现场运行实践表明该磨底机床达到了预期效果。     

APMP制浆叶高浓盘磨机的一种控制系统的设计

根据某纸厂引进的APMP浆线中高浓盘磨机的自动控制系统,设计一种新的盘磨机控制系统,利用专家控制方案,主要进行硬件、软件设计,以及盘磨保护措施的设置,并对运行结果简单分析,说明了此控制系统能提高盘磨机的工作效率和磨浆质量.     

金相试件自动磨抛机结构设计及分析

为了解决薄板类金相试件手工磨抛控制难、效率低且易产生弧形端面的问题,设计一种无需镶嵌的新型自动磨抛机。首先通过对薄板类金相试件手工磨抛过程分析,确定了试件磨抛的工作原理和技术要求,制定了自动磨抛机的结构和运动方案,详细设计了夹持装置A和夹持装置B的结构;然后建立基于有向装配原理的整机装配连接关系模型,并利用UG软件实现了磨抛机的有向装配;最后对所设计磨抛机的性能进行试验验证。结果表明:经所设计的自动磨抛机磨抛后的试件相比手工磨抛,平面度误差减少了62.5%(端面弧高H_2约为15μm),垂直度误差减少了50%(垂直度误差仅0.04μm),表面粗糙度Ra降低了20%(表面粗糙度Ra仅为0.08μm)。该磨抛机整体性能优于技术要求和手工磨抛水平,而且磨抛效率高,劳动强度低。     

摩擦过程中磨屑运动的分析

制动摩擦材料和铸铁摩擦盘在摩擦过程中产生磨屑。磨屑对摩擦层的形成、组成及其动态平衡、摩擦机制以及摩擦性能起着重要作用。为了理解磨屑对摩擦层形成的影响,以国家标准(GB5763-2008)中第4类盘式制动器用衬片规定的定速摩擦性能测定仪和测试条件,对四类磨屑(拖曳、跃迁、振动和碰撞)分别在摩擦材料和摩擦盘之间的三维空间运动的受力状态、运动轨迹和动力学行为进行了分析。结果表明,磨屑的运动轨迹是一个不规则运动,磨屑之间会发生碰撞。在摩擦过程中,磨屑可以飞离摩擦盘,也可以聚集在摩擦材料和摩擦盘表面形成摩擦层。     

航空发动机盘类零件滚磨光整加工的模拟

为探寻航空发动机盘类零件滚磨光整加工一致性的最优方案,进一步提升滚磨光整加工技术在航空发动机盘类零件表面光整加工中应用的有效性,基于离散元法对航空发动机盘类零件分别进行振动式、回转式和离心式三种滚磨光整加工方案的模拟分析。对比典型区域工件和磨块颗粒的速度、磨块颗粒与工件的接触力,并通过"Hertz-Mindlin withArchard Wear"模型对盘类零件的磨损情况进行计算对比。通过模拟分析得出,同一种方案中不同区域处工件及磨块颗粒的速度、磨块颗粒对工件的接触力均不相同,与各区域所处于磨块颗粒介质流场中的空间位置有关;不同方案中盘类零件的磨损情况均不相同,与不同方案的加工原理、工艺参数有关;一定条件下,振动式滚磨光整加工较回转式和离心式滚磨光整加工,一致性明显较好。该模拟分析方法可对航空发动机盘类零件加工方案的选择、工艺过程的控制和优化提供参考依据,最终提高加工效率。     

叉轴式强力滚磨加工对工件表面完整性的综合改善

通过扫描电观察并研究加工前后表面形貌和表面变质层厚度的变化,测试并分析加工前后试件表面显微硬度、表面应力状态物理机械性能,对典型盘类零件进行了滚磨加工试验,研究表明,叉轴式强力滚磨技术是改善大中型盘类零件表面质量,提高使用性能的理想工艺。     

电刷镀修复机床磨损件

1.单轴自动车床回转刀盘的修复 单轴自动车床大修中,恢复回转刀架精度是主要修理项目,一般需对回转刀盘(图1)的锥度抽颈及台阶面进行修磨后配刮回转刀架体锥孔。回转     

钕铁硼材料在磨抛光盘中的应用

针对自动金相研磨抛光机磨抛光盘加工精度高、互换困难、磨抛过程中易产生噪声等问题,通过对钕铁硼材料的测定,提出采用在磨抛光盘上镶嵌磁性材料钕铁硼的方法,研制出磁性磨抛光盘。实验证明,磁性磨抛光盘换取轻便,降低了噪声,提高了试件的磨抛光精度。     

一种自动磨钎机的设计

钎头是一种凿岩工具,现有磨钎方式多采用手工操作方式,磨削时产生的剧烈振动,工人的劳动强度很大,且也很不安全.现设计一种自动磨钎机,自动磨钎要求定位精确,工作安全可靠,通过气一电自动控制方式和可编程控制器(PLC)实现自动磨钎机构的定位、转向、换面等动作.详细介绍了该自动磨钎机的机构、工作原理和工作流程.样机测试结果表明...     

双盘拉丝机自动换盘装置的设计

针对双盘拉丝机换盘速度慢、效率低的问题,对新型自动换盘装置和工字轮进行了结构和换盘方案的设计.从理论上分析了自动换盘装置的工作原理和流程;通过UG对自动换盘装置和工字轮进行了三维建模,运用ANSYS软件对工字轮和自动换盘装置的结构进行了静力学分析,得出了自动换盘装置和工字轮在实际工作时的应力应变云图;通过动力学仿真分析...     

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.