齿形滑环式组合密封的有限元分析

利用ANSYS建立齿形滑环式组合密封的二维轴对称模型,分析压缩量、介质压力及齿形滑环结构对组合密封的接触应力、变形、Yon Mises应力及剪应力的影响.结果表明:随着压缩量的增加,组合密封的变形及接触应力增大,O形圈的受力减小;随着介质压力的增加,组合密封的变形、接触应力及O形圈的受力增大,因此,在较大介质压力条件下,应适当增加压缩量;适当改变齿形滑环的尺寸,可以使得O形圈受力减小,且齿形滑环不易磨损,使用寿命延长.     

齿形滑环密封圈密封性能分析及结构改进

建立了齿形滑环密封结构数值计算模型,采用有限元方法分析0形密封圈和滑环的接触应力和应力分布,并探讨介质压力、往复速度、摩擦系数和压缩量对密封性能的影响.结果表明,在静密封阶段,0形密封圈横截面内部应力集中在靠近凹槽底部区域,滑环足部与中间接触部位的变形严重.随着压缩量、介质压力的增加,齿形滑环密封圈密封性能和变形增加,...     

滑环式组合密封件的研究(Ⅱ)——阶梯形同轴密封件(斯特圈)的有限元分析

利用ANSYS建立了滑环式组合密封圈中应用较广泛的阶梯形同轴密封件（斯特圈）的二维轴对称模型,分析了滑环厚度对密封圈的变形和密封面处接触应力的影响;压缩量对密封件的接触应力、变形和VonMises应力的影响;液体压力对密封圈变形、密封面处接触应力和接触宽度的影响,结果证明随滑环厚度增加,滑环抵御变形的能力增强,密封面处的接触应力增大;压缩量越大密封件VonMises应力增加,变形增大,接触应力出现突变;随液体压力增加,O形圈和滑环变形增大,密封面处接触应力和接触宽度增加。     

电液伺服摆动马达的密封泄漏与摩擦特性

为了提高电液伺服摆动马达的密封效果,借助于有限元软件ADINA对采用聚四氟乙烯密封件和O形圈的组合密封在不同密封结构、预压缩量和介质压力下进行接触应力分析;由缝隙流动原理推导泄漏量和摩擦力之间的关系;综合考虑密封泄漏量和摩擦力,确定适合于摆动马达的密封结构形式及预压缩量;利用摩擦磨损试验机测试聚四氟乙烯在相同介质压力、不同频率下的摩擦因数,分析其摩擦情况。结果表明,O形圈预压缩量为20%时具有较好的密封效果;星形密封件具有更高的耐压能力,更适合于摆动马达的应用场合;聚四氟乙烯的摩擦因数随着工作频率的增加而减小,说明其适合在高频率的条件下工作。研究表明,该组合密封符合电液伺服摆动马达的动态性能要求。     

O形圈三角形密封槽设计改进

介绍了O形圈角密封槽的结构特点及压缩量的计算方法.针对某角密封槽设计泄漏故障,利用有限元分析软件Ansys分析O形圈不同受力下的接触应力.通过分析发现泄漏的原因为:三角形密封槽结构O形圈受介质力后,轴向接触应力明显减小.根据分析结果制定改进方案,通过改变三角形密封槽的角度以减小介质力对接触应力的影响,解决泄漏问题,为三...     

充气式柔性密封的非线性有限元分析

从V形橡胶密封圈结构特点和密封可靠性出发,考虑结构的材料非线性、几何非线性和接触非线性,建立了充气式柔性密封的轴对称有限元模型,对其充气密封机制进行了分析,得到了密封面法向接触应力的分布规律;讨论了不同的充气压力和密封介质压力对法向接触应力的影响.结果表明,实现有效密封的关键是使法向接触应力高于密封介质压力,而法向接触应力的大小随充气压力的增大而增大;密封介质压力的存在使得接近密封介质一侧的接触压力减小,进而密封面的长度减小,影响密封效果;最大von Mises应力主要集中于与刚性件尖角接触处以及内壁的圆弧面上,且随充气压力的增大而增大;合理的密封结构和充气压力可保证密封的效果和可靠性,同时也可延长橡胶密封圈的使用寿命;利用有限元软件ANSYS进行充气式柔性密封圈结构设计和优化是可行的.     

T形滑环组合密封圈密封性能研究

利用ANSYS建立T形滑环组合密封的二维轴对称有限元模型,将密封结构划分为4个密封区域,研究静、动密封状态下介质压力、密封间隙、摩擦因数和T形滑环斜边与垂直线之间的角度,对组合密封圈密封性能的影响。仿真结果表明,T形滑环组合密封可以满足研究的压力范围下的静、动密封要求。其最大Von Mises应力和最大接触应力随介质压力增大而增大,随密封间隙增大而减小;最大Von Mises应力和最大接触应力随滑环斜边与垂直线之间角度增大而增大,当角度为2.5°～7.5°时,组合密封可达到密封要求且滑环不易磨损;摩擦因数越小,组合密封动密封性能越好。     

成品油库主输泵出口阀门不同密封结构性能分析

以某成品油管道闸阀为研究对象,建立阀杆处密封结构的分析模型,研究3种不同密封结构中密封效果与介质压力之间的关系,提出阀杆处密封性能的综合评定方法。结果表明：阀杆处密封性能可从密封接触面间最大接触应力、密封件实际工况下米塞斯应力峰值和密封件在密封介质压力作用下的变形情况3个方面进行综合评定。研究的3种密封结构无能满足密封的要求,其中V形沟槽内密封圈的密封能力最强,矩形沟槽内滑环式组合圈的密封能力最差;在相同工况下V形沟槽内密封圈米塞斯应力峰值最大,矩形沟槽内滑环式组合圈米塞斯应力峰值最小;组合圈与矩形沟槽配合的结构能有效解决密封件被挤入沟槽的情况。     

径向弹簧蓄能密封结构最大接触应力的有限元分析

为研究径向弹簧蓄能密封结构的密封特性，针对典型径向弹簧蓄能密封结构，分析其密封机制以及O形弯曲金属螺旋弹簧的弹性特性；采用ANSYS有限元分析软件，建立典型弹簧蓄能密封结构的非线性有限元分析模型，对弹簧蓄能密封圈在不同压缩率、不同介质压力下的接触应力进行分析，研究在多种工况下最大接触应力的变化情况。结果表明：压缩率保持不变时，最大接触应力随着介质压力的增大而增大；介质压力保持不变时，随着压缩率的增大，最大接触应力先增大再减小。对压缩率、介质压力与最大接触应力的关系进行曲线拟合，可用于指导弹簧蓄能密封结构的精确设计。     

星形橡胶密封圈的密封特性分析及截面改进

建立了X形(星形)密封圈的有限元计算模型,研究了预压缩量、摩擦因数、介质压力、橡胶硬度对其密封性能和力学性能的影响。为提高密封圈的密封性能,延长使用寿命,对其横截面形状进行了改进,并对其静密封和往复动密封性能进行了分析。研究结果表明,X形密封圈的Von Mises应力和接触应力随着摩擦因数的增大而逐渐降低,但随介质压力、橡胶硬度的增大而增大;而结构的特殊性使得X形密封圈Von Mises应力随预压缩量的增大而减小;改进密封圈不但继承X形密封圈的优点,而且实现了三道密封功能,在保持良好密封性能的同时改善了结构的应力集中现象;特别是在往复动密封中,改进密封圈的应力波动较小,密封性能优于X形密封圈,避免了X形结构触角过早发生疲劳失效和撕裂,延长了密封圈的使用寿命。     

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.     

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。     

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....     

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.