水润滑石墨推力轴承可靠寿命研究

水润滑石墨推力轴承是影响屏蔽泵可靠寿命的关键部件,本文依据可靠性理论,导出了水润滑石墨推力轴承可靠寿命的数学模型,并通过屏蔽泵水润滑石墨推力轴承的寿命试验数据对模型中的参数进行了估算,此研究成果对水润滑轴承可靠寿命预测及设计计算具有普遍的指导意义.     

普通车床车削带螺纹的薄壁零件

水润滑石墨推力轴承是影响屏蔽泵可靠寿命的关键部件,本文依据可靠性理论,导出了水润滑石墨推力轴承可靠寿命的数学模型,并通过屏蔽泵水润滑石墨推力轴承的寿命试验数据对模型中的参数进行了估算,此研究成果对水润滑轴承可靠寿命预测及设计计算具有普遍的指导意义。     

屏蔽泵石墨推力轴承强度的可靠性计算

综合运用润滑理论、可靠性理论并使用有限元法求解屏蔽泵石墨推力轴承的可靠性，此方法亦可在其他不同材料的推力轴承瓦面上各节点处的可靠性计算中使用。     

核主泵水润滑推力轴承试验磨损颗粒研究

某核主泵水润滑推力轴承在试验浸银石墨瓦时,在类似热瞬态工况时出现异常振动及噪声,拆机发现石墨推力瓦和推力盘硬化层表面均出现较严重磨损,且石墨推力瓦出现局部剥落。采用化学、光学、X射线衍射、扫描电镜、透射电镜、电子探针等方法研究水润滑轴承试验的磨损颗粒相结构、形貌、成分、组织和磨损表面特征;明确热瞬态时不锈钢推力盘硬化层与石墨推力瓦的摩擦磨损形式和过程,得出水润滑推力轴承已经进入边界润滑状态,局部发生干摩擦的结论;提出一些改进建议,如将水润滑轴承瓦面材料改为碳素纤维复合材料以增加抗磨性能,改善瓦面形状以减少热变形,增加接触曲面硬化层以控制高应力曲面接触的微动磨损。     

核主泵水润滑推力轴承试验的磨损颗粒研究

某核主泵水润滑推力轴承在试验浸银石墨瓦时,在类似热瞬态工况时出现异常振动及噪声,拆机发现石墨推力瓦和推力盘硬化层表面均出现较严重磨损,且石墨推力瓦出现局部剥落。采用化学、光学、X射线衍射、扫描电镜、透射电镜、电子探针等方法研究水润滑轴承试验的磨损颗粒相结构、形貌、成分、组织和磨损表面特征;明确热瞬态时不锈钢推力盘硬化层与石墨推力瓦的摩擦磨损形式和过程,得出水润滑推力轴承已经进入边界润滑状态,局部发生干摩擦的结论;提出一些改进建议,如将水润滑轴承瓦面材料改为碳素纤维复合材料以增加抗磨性能,改善瓦面形状以减少热变形,增加接触曲面硬化层以控制高应力曲面接触的微动磨损。     

屏蔽泵冷却润滑回路分析计算

屏蔽泵是机泵一体结构,具有绝对无泄漏的特点。屏蔽电机工作时产生的热量由冷却润滑液带走,同时屏蔽泵的导轴承、推力盘需要润滑冷却。因此屏蔽泵的冷却润滑回路是保证屏蔽电动机正常工作的必要条件。通过对冷却润滑回路的简化,计算出各个阻力元件的阻力降和总的循环扬程,结合一个化工屏蔽泵实例,对比分析了循环扬程的计算结果与实测结果。验证了该简化方法的可行性,对提高泵的效率、增加泵的运行寿命具有实用价值。     

屏蔽泵水润滑石墨推力轴承摩擦学性能的研究

本文分析了影响水润滑石墨推力轴承摩擦学性能的主要因素,如润滑水膜厚度、温升、载荷及转速、轴承材料的性能等,提出了提高水润滑轴承摩擦学性能的主要方法,如创建容易获得稳定润滑水膜的工况条件,缩短轴承的启动时间,减小轴承负载,选用合适的摩擦副材料等。     

水润滑推力轴承推力瓦应力场分析

水润滑推力轴承工作时,推力瓦和推力环端面间的高速相对运动会产生大量摩擦热,导致端面温升和热变形,使推力瓦产生局部高温和高应力,影响水对推力轴承的润滑效果、传递轴向推力效果、轴承寿命和安全性。基于ANSYS软件平台,建立水润滑推力轴承斜面平台固定推力瓦危险截面有限元分析模型,分析推力瓦危险界面的变形和应力场。结果表明:推力瓦的最大变形和最大Von Misses应力均出现在离推力瓦进水方向2/3瓦长处。     

水润滑轴承在水轮泵上的应用及推力瓦块主要参数的确定

本文主要叙述用水润滑轴承代替金属滚动轴承,解决了水轮泵潜水工作由于金属滚动轴承密封困难而影响使用的大问题。对结构不同的轴承作了大量的试验,基本掌握了影响水润滑轴承寿命的几个重要因素,推导了推力轴承承压面和润滑水槽间关系的计算公式,并用统计法推荐了推力瓦块主要的参数,达到了农机部颁布的水润滑轴承运行5000小时磨损2毫米的规定,为设计人员提供了设计依据。     

水润滑推力轴承承载力影响因素及提高方法研究

阐述了水润滑轴承承载特点。结合某特定工况下主泵电机中水润滑推力轴承的设计．对影响水润滑推力轴承承载力的因素进行了分析，并提出了提高水润滑轴承承载力的方法。     

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.