硬支承动平衡机平面分离解算的误差分析

本文在硬支承动平衡机平面分离解算的通用模式基础上,进一步分析其误差来源,为评价硬支承动平衡精度指标提供了依据。     

动平衡测试技术方法浅析

阐述了硬支承和软支承两种动平衡机的平衡原理，简要分析了影响系数法、小波变换法和互相关法这三种不平衡量的提取算法，并介绍了目前常用的几种动平衡机的结构形式。     

气浮立式硬支承动平衡机研究

基于气浮轴承支承技术，设计了硬支承立式双面动平衡机，建立了相应的数学模型。经过双力传感器测量系统进行数据采集和处理，得到两个分离平面上的不平衡量，通过配平使得旋转体的不平衡量有很大的减小。实验验证表明，这种动平衡测量方法是合理和有效的，整个动平衡机系统工作稳定，有较高的测量精度和配平效果。     

外悬航空涡轮转子的平衡

本文重点讨论了校正面外悬的航空涡轮转子在配有微机化电测系统的硬支承动平衡机的环境下进行平衡的最佳方法－准静－偶分离平衡法，并介绍了在黎明发动机制造公司总装厂对外悬航空涡轮转子试用以用支承动载荷作为外悬转子动平衡检验唯一标准的初步实践情况。     

基于DSP的数字式动平衡测量系统及其关键技术的研究

为满足动平衡测量与加工一体化的动平衡自动校正技术发展的需求,文中采用高性能的DSP芯片作为中心测控单元,实现了一个可单机或同数控加工系统联机应用的数字式动平衡测量系统.在对系统总体结构介绍的基础上,重点对一些关键技术进行了讨论,首先,针对硬支承方案,分析了测力支承机械振动系统振动特性并整定了硬支承设计的重要参数;其次,提出采用程控增益放大的方法实现信号的跟踪调理,提高了测量系统的精度.系统已得到了实际应用,结果表明系统具有可靠、高精度和使用方便等特点.     

硬支承平衡机原理误差的消除及新型平衡机的构想

根据目前普遍使用的硬支承动平衡机存在的原理误差并且机械灵敏度较低的问题,对原理误差进行了简要分析,介绍了降低原理误差的各种措施,并提出了新一代动平衡机的设计构想.     

刚性转子动平衡的关键技术分析

阐述了刚性转子双面硬支承动平衡的工作原理,介绍了转子不平衡量的提取算法和数字滤波方法,分析了动平衡系统标定方法、去重校正策略及误差补偿等关键技术.     

基于B样条的高频比动平衡机的永久标定实现

提出了一种基于双三次B样条插值对刚性转子动不平衡测试系统进行系统标定的方法,该方法可以避免和减少硬支承动平衡测量系统中由于忽略了惯性力和系统阻尼带来的测量误差,实现硬支承和软支承动平衡测量中系统的永久标定。在德国申克ST590平衡电测系统中采用0.5kg、1.6kg、5kg、16kg转子分别在180～1423r/min转速范围内进行标定实验,实验结果表明,该方法的标定结果与状态标定的标定结果具有同等的标定精度和测量精度。     

曲轴在硬支承动平衡机上的试验与去重

通常的曲轴动平衡试验是在专用的“软支承”动平衡机上进行的。这类平衡机设计有平面分离解算网络,利用机械或电气的标准转子进行平面分离及标定,能显示校正面(各个平衡块)上的不平衡量大小与相位。但是,这类平衡机也有缺点,如调整标定费时、精度低、故障率高和不适宜进行初始不平衡量大的曲轴动平衡等。将硬支承动平衡机应用于曲轴试验的困难是校正面与去重面之间的换算关系不够明     

软支承动平衡机的CAB技术研究

运用影响系数矩阵构造软支承动平衡机支承的振动数学模型，设计计算机辅助动平衡（ＣＡＢ）测试系统。给出ＣＡＢ技术在３ｔ动平衡机上的应用实例，结果证明，一次不平衡量的消除可达９２％以上。     

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.