铁谱技术在判断发动机磨损状态中的应用研究

发动机中各摩擦副的工作环境恶劣,磨拟状态复杂,很难精确描述。而发动机所处的磨损状态是判断其是否正常工作的重要标准,因此建立发动机磨损状态监测具有重大的经济和社会效益。笔者利用铁谱技术作为一种监测手段,通过磨粒分析来判断发动机的磨损状态。     

发动机铁谱磨粒分析与磨粒识别研究

从发动机摩擦副及其摩擦磨损特点着手，提出了用于发动机磨损状态监测与诊断的主要10类磨粒，依据其识别特征提出了用于磨粒识别的14个磨粒形状、表面纹理与颜色特征；最后应用BP网络分层识别策略进行了磨粒识别。     

冬季使用工程机械的防磨损措施

1.避免机器运转时产生干摩擦和临界摩擦 机器运转中的干摩擦和临界摩擦状态会加剧机件的磨损,造成机械效率下降,甚至引发机械事故。资料表明:发动机启动时的磨损量占其全部磨损量的75％,这么大的磨损量是因为启动时发动机各机件没有足够的润滑油润滑而处于临界摩擦或干摩擦的工作状态下造成的,所以,缩短启动时间、及时形成良好的润滑状态是减少磨损量的     

基于有序样品聚类和模糊理论发动机状态监测研究

提出基于有序样品聚类和模糊理论发动机状态监测研究方法。利用有序样品聚类方法,对油液铁谱分析数据进行分类,实现了发动机的状态监测;利用模糊理论方法,结合发射光谱分析数据判断发动机的异常磨损部位。采用该方法对康明斯6BT5.9型柴油发动机状态进行监测,确定发动机可能出现异常磨损的部位,与发动机解体实际检查结果一致,证明上述研究方法对发动机异常磨损部位的确定具有一定的适用性。     

基于偏最小二乘回归分析发动机异常磨损的判断

针对发动机状态监测中油液光谱分析样本数据少、元素种类多及各元素之间存在相关性的特点,提出采用偏最小二乘回归方法处理油液光谱分析数据。分析了偏最小二乘回归方法的特点,阐述了其基本原理和算法步骤;将偏最小二乘回归方法应用于发动机油液光谱数据的处理和分析,求出了发动机磨损状态判断的回归模型;应用此回归模型判断了EQ6BT柴油发动机的异常磨损。结果表明,应用此回归模型可以直观地判断发动机是否存在异常磨损。     

基于能量耗损的发动机故障诊断方法研究

针对发动机在发生故障时都伴随能量耗损变化,提出一种基于能量耗损的发动机故障诊断方法.基于发动机系统输入输出的能量分析,建立发动机系统的能量监测模型;根据输入的流量与输出的功率,建立发动机系统的能量耗损模型;根据能量耗损机制,分析发动机运动副的摩擦与振动能量耗损诊断方法,建立摩擦和振动信息与能量耗损模型.以发动机活塞磨损故障为例,从振动耗能的角度,通过对测振信号的小波分析,得到能量耗损变化,诊断出活塞的磨损状态,验证了基于能量耗损的发动机故障诊断方法是可行的.     

径向滑动轴承金属磨损自修复实验机研制

基于通用摩擦磨损实验机设计思想,模拟边界条件下的径向滑动轴承,依据金属磨损自修复边界润滑状态下发生的特点,应用自主开发的润滑状态判断软件,研制了径向滑动轴承金属磨损自修复实验机。介绍了该实验机的设计原理及特殊功能,采用该实验机进行了自修复实验。实验结果证明,金属磨损自修复专用实验机能模拟实际工况润滑状态和工况载荷,具有实时监测摩擦副胶合和磨损失效瞬间状态,在线测量摩擦副温度、摩擦扭矩、振动加速度、试件转速及摩擦力等功能,并能实现急停,可用于金属摩擦磨损自修复保护膜生成机制的研究。     

发动机零部件磨损量的光谱测量数值分析与试验研究

建立新发展的分析模型,采用适当的数值计算方法,对光谱分析数据进行处理,以得到发动机各零部件在运行过程中的实际磨损量,并将这一技术应用于发动机零部件磨损试验。初步验证了这一技术应用于发动机摩擦、磨损分析、试验研究和运行监测、故障预测诊断的可能性,为今后发动机摩擦、磨损分析、试验研究和运行监测及故障预测、诊断提供了有益的途径。     

基于油液降噪信息的发动机磨损多特征分析研究

由于难以确定合适的油液检测数据处理方法,应用油液分析监测发动机磨损状态的有效性和针对性不高。为此,根据经小波包降噪的光谱数据和直读铁谱数据,在用新三线值法提取边界特征及用K-means聚类法获取质心特征的基础上,提出了质心-边界多特征分析方法,以确定发动机主要摩擦副的磨损状态。结果表明,多特征分析法比传统三线值法更详细、准确,使磨损状态的识别率提高一倍。信号的相关特征研究表明,活塞环摩擦副的磨损出现了异常,进一步证实了多特征分析的准确性和有效性。     

发动机缸套-活塞环摩擦磨损特性试验研究

利用缸套-活塞环摩擦磨损试验台研究了速度，温度，载荷，供油等因素对缸套-活塞环系统摩擦磨损特性的影响。试验结果表明，缸套-活塞环摩擦副在发动机工作循环中润滑状态不断发生变化。在试验条件下，温度对摩擦磨损有显著影响，载荷和速度对摩擦力的影响较小。     

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.