基于重分配小波尺度图的转子系统支座松动故障的研究

介绍了重分配小波尺度图，并通过分析仿真信号将传统小波尺度图与重分配小波尺度图进行比较，结果发现重分配小波尺度图可在一定程度上提高尺度图的聚集性，减少干扰项。通过建立转子松动故障的仿真实验台，把实验采集到的发生松动故障的振动信号，利用重分配小波尺度图和三维谱振图进行分析，结果表明，三维谱振图可以大体上显示频谱信息，重分配小波尺度图可以进一步对松动故障信号进行细化分析，两者结合可以更好地识别转子支座松动故障。     

基于小波变换的电气设备故障诊断技术

小波变换具有良好的时-频特性，因此可以有效地用于电气设备故障诊断。在对电气设备进行故障分析、诊断过程中，利用小波变换进行故障信号的故障时刻检测具有重要意义。小波变换用于电气设备故障诊断就是对电气设备各种电磁、机械等信号进行实时监测控制，判断其状态，以便在故障初期或故障时刻发出警报，并随时进行处理，排除故障。对信号进行特征提取，是故障诊断的关键。突变信号往往表明电气设备发生了某类故障，如果能对突变信号进行有效识别，就可以进行故障诊断、故障分析，从而排除故障。分析了电气设备故障的奇异性，通过仿真得出小波变换用于电气设备故障诊断的方法，以准确检测奇异点，确定故障时刻。     

小波分析和神经网络技术在故障诊断中的应用

介绍了智能诊断技术、小波分析技术及神经网络技术，阐述了小波与神经网络相结合的两种方式——松散型小波神经网络和紧致型小波神经网络。在此基础上，以松散型小波神经网络对刀具故障的在线监测为例，说明了小波分析和神经网络技术对刀具故障进行在线监测，故障预报正确率为87.7％。     

小波分析在往复压缩机故障诊断中的应用

由于往复压缩机的振动特性比较复杂，振动信号是非平稳信号，而小波分析非常适合分析非平稳信号。阐述了小波分析的基本原理，并应用多分辨率分析和小波包分析对往复压缩机故障振动信号进行处理，取得了很好的效果。     

基于改进小波神经网络的旋转机械故障诊断

根据旋转机械复杂的故障特点，提出了结合第2代小波分析、模糊理论和神经网络形成的改进小波神经网络。该诊断方法利用第2代小波分析对信号进行预处理-征向量的提取，然后用训练好的模糊神经网络进行故障识别，并对相应算法进行了优化。将改进小波神经网络运用于旋转机械的故障诊断，通过计算机仿真和试验的结果表明，该方法在处理多故障耦合的情况时优势明显，不仅可以正确识别故障的类型，还可以进一步对故障的严重程度及其发展趋势进行可靠的诊断。这表明改进的诊断方法是行之有效的，为旋转机械的故障诊断提供了理论支持。     

小波分析技术在汽轮机故障诊断中的应用研究

本文就小波分析技术在汽轮机故障诊断应用中的故障特征提取问题进行了深入研究，提出了基于小波能量分布的故障特征提取方法，并在转子试验台上进行了验证。实践检验证明，该实现方法能够满足汽轮机振动信号分析的需要，是一种灵活有效的特征提取方法。     

基于Modet小波的滚动轴承故障信号奇异性分析

针对滚动轴承故障信号分析中单一频域表征的问题，提出了将Morlet连续小波变换应用于故障信号奇异性提取和分析的新方法。在分析了滚动轴承故障信号的奇异性特征和奇异性信号小波检测机理的基础上，将Morlet连续小波用于对滚动轴承故障信息的提取与分析。试验证明，该方案能有效地对滚动轴承故障信号在时间和尺度平面进行分析，可以同时表征奇异性信号的时间和频率信息。     

连续小波变换在滚动轴承故障诊断中的应用

针对滚动轴承故障振动信号的特点，构造脉冲响应小波，采用连续小波变换的方法来提取滚动轴承故障振动信号的特征，在此基础上提出了两种滚动轴承故障诊断方法：尺度——小波能量谱比较法和时间——小波能量谱自相关分析法。通过对滚动轴承外圈和内圈故障振动信号的分析，说明两种方法不仅能检测到滚动轴承故障的存在，而且能有效识别滚动轴承的故障模式，从而为滚动轴承故障诊断提供了一种新途径。     

基于连续小波灰度图的变速箱故障诊断

为了诊断汽车变速箱的周期性冲击故障，利用连续小波变换灰度图分别对正常和故障汽车变速箱振动信号进行了分析。结果发现，连续小波灰度图不仅能识别变速箱的正常与故障，准确提取出周期性冲击故障信息，而且能够非常直观形象地表达出信号的细微结果，并进一步显示出故障变速箱中同时存在的两种相同频率的故障信息，从多层次、多方位观察到了分析信号的细微变化。     

小波分析在高速旋转机械故障特征提取中的应用

简述了小波分析基本原理及其用于故障特征识别的机理,并运用小波分析理论对轴承座松动早期故障成功的进行了特征提取,体现了小波分析的良好性能。     

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.     

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....     

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.