基于振动监测的海上油田主海水泵故障诊断分析（英文）

主海水泵是某海上浮式生产储油船(FPSO)的关键设备。受船体变形、海水腐蚀、机组刚性底座及进出口管线应力等因素影响,机组振动值异常突出,故障频发。为此,通过定期离线监测,利用频谱分析技术研究了振动幅值规律,对主海水泵故障进行了诊断,得到了设备报警参考值和停机值以及故障周期。实现了设备预知性维修,从而预防恶性事故发生。     

煤矿水泵机组常见故障及其特点

主要以图解的方法详细分析煤矿水泵机组电机转子和电机轴承故障特点及其产生原因,其中,电机转子故障包括转子不平衡、转子不对,电机轴承故障包括油膜振荡、转轴横向裂纹;同时分析由于泵内异物引起的水泵机组振动的特征,并以河南郑泵科技有限公司生主的矿用耐磨多级离心泵为例,分析泵内汽蚀余量对水泵机组生命周期和使用效率的影响。     

水泵振动原因分析及处理方法

机组、水泵是电厂发电机正常运行的基础,如果水泵不工作,势必导致电厂汽轮机故障,影响电厂正常运行。水泵振动是引起水泵故障的主要因素之一,但实际运行中水泵振动有多种原因。如果维修人员在短期内不了解引起水泵振动的因素,水泵将始终处于振动状态,大大降低水泵的效率,进而影响电厂的出力,水泵的振动也会随之产生。本文对水泵振动原因进行了分析,提出了消除水泵振动的方法。     

水泵机组异常振动诊断

对某水泵机组异常振动进行精密诊断,找出振动原因,排除了故障。     

武钢R4轧机主传动系统减速机的故障诊断

针对武钢热轧厂1700热连轧机组R4轧机主传动系统工作中振动强烈、设备事故频繁的实际问题,在轧机实际生产的条件下,对该轧机主传动系统的减速机的振动信号进行监测,在此基础上运用振动诊断法进行故障诊断,预测了该设备存在的故障并分析研究故障产生的主要原因。     

热连轧机组轴承及主传动系统振动诊断分析

某厂热连轧机组由于压下率大,品种规格多,对设备的承载能力提出了更高要求。在日常的在线监测中发现F4轧机主传动系统出现异常振动,对采集信号进行自适应小波降噪处理,分析测试信号的频率特征,对应轴承故障频率的理论计算值,发现F4轧机主传动系统减速箱高速轴轴承是异常振动的故障源,判断缺陷发生在滚动体上。在设备检修时,更换了主传动系统减速箱高速轴轴承,设备异常振动消失,与计算结果相符。实际观察更换后的减速箱轴承,发现和预测结果一致。     

应用水力优化分析对水泵机组减振研究

对某船用水泵机组进行振动测试,通过机组的特征频谱分析,找出其可能对应的影响因素。通过水泵机组模态测试出的参数结果分析,发现自身结构及安装基础不是引起该特征谱线的主要原因。再应用流场分析方法对水泵机组的水力模型进行有限元仿真分析,包括吸水室流道、叶轮流道和压水室流道,找出影响振动的流体激励因素。最后根据流场分析的结论,改进优化了水泵机组的叶轮水力模型,消除了水流速度线旋涡现象。成功地应用水力优化技术抑制了振动谱系中特征峰值的幅值,有效地降低了水泵机组低频振动值。     

设备冷却水泵转子系统振动特性研究

通过对水泵机组动态特性测试分析,结合故障诊断分析,获知设备冷却水泵在正常工作条件下因不平衡载荷引起的转子振动情况。一方面结合模态测试与有限元仿真的方法,找出安装边界条件对水泵机组转子系统的振动影响,并进行部分结构的改进;另一方面采用有限单元法,计算转子在不平衡激励条件下的瞬态响应,分析转子振动的位移频谱和关键位置的支承力响应频谱,获得关键位置的振动位移、作用力的幅值以及频率信息。分析结果将用于设备冷却水泵整机的振动噪声分析,并研制出新型的复合阻尼转子系统。     

离心式压缩机组振动原因分析及处理北大核心

对离心式压缩机在运行中存在轴瓦温度升高、机组振动值过大等问题进行分析,找到了引起机组故障的主要原因,结合生产实际,在检修中采取相应措施解决了设备运行故障,保证了机组的平稳正常运行。     

大型泵站主机组振动测试与分析

结合南水北调东线相关泵站的改造工程,运用CRAS振动信号采集与分析处理系统对水泵机组的振动情况进行现场测试。这为弄清改造后的机组在不同工况下运行时的振动情况提供了技术数据,同时这也给配备相同类型水泵机组的其他泵站的改造提供了参考依据。经现场测试,该泵站改造后的机组在一定叶片角度下其振动值随着电机输入功率及扬程的增大而减小,且机组电机层下层顺水流方向上的振动值比较大,机组的轴向振动较小。     

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.     

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.