带式输送机的新型驱动

带式输送机的新型驱动北京起重运输机械研究所杨乃乔，邹铁汉延长起动时间和降低起动加速度是带式输送机当前技术发展中的焦点，尤其是长距离的和有水平弯曲的输送线，对此要求更为突出。通常人们采用限矩型液力偶合器（例如常用的ＹＯＸ或ＴＶ型动压泄液式液力偶合器）来...     

内轮驱动液力偶合器的利弊与合理使用

普通型、限矩型液力偶合器通常采取外轮驱动方式使用,但有些特殊情况下也有采用内轮驱动的。无论采用哪种类型的液力偶合器,采用电动机与其内轮相连接进行驱动的,称其为内轮驱动液力偶合器。内轮驱动液力偶合器的特点1.优点内轮驱动液力偶合器有利于主体重量承载于电动机轴上以     

限矩型液力偶合器型式试验台的研制

介绍限矩型液力偶合器结构组成及工作原理,搭建限矩型液力偶合器型式试验平台,阐述试验台系统组成、软硬件实现,可实现液力偶合器性能测试,并能实时监测运行状态、实时采集数据、自动处理和存储数据等。试验结果表明,限矩型液力偶合器试验台性能稳定可靠,操作简便、自动化程度高,能够满足限矩型液力偶合器型式试验的要求。该试验台的研制为改进限矩型偶合器产品性能具有重要的意义。     

限矩型液力偶合器匹配选型常见问题探讨

该文阐述了限矩型液力偶合器匹配选型的一般原则；对限矩型液力偶合器匹配选型实践中常见的问题进行了分析，指出了其带来的影响及产生的原因。     

YOX500A型液力偶合器的特性及其模拟试验

为研制新的限矩型液力偶合器以满足长距离带式输送机驱动单元急需,本文介绍YOX500A型液力偶合器样机的结构特点、关键技术,并结合模拟试验分析其特性曲线以及样机的推广应用。     

限矩型液力偶合器多流动域耦合流场特性模拟

限矩型液力偶合器内部两相介质在多流动域内做着复杂的耦合流动。为掌握限矩型液力偶合器内部流动规律,更好地指导限矩型液力偶合器的设计与优化,以YOX500型限矩型液力偶合器为研究对象,采用Mixture两相流模型及RNG k-ε湍流模型对其在3种典型充液率不同工况下的流场进行瞬态模拟。结果表明:随着转速比的升高,偶合器内部流动逐渐由大环流转变为小环流,压力趋于均匀带状分布;同时对其外特性进行计算,模拟所得结果与试验结果吻合较好,证明了该方法的有效性;但该方法不能直观地体现偶合器转矩的跌落情况,因此具有一定的局限性。     

限矩型液力偶合器气液两相环流特性仿真

为了研究限矩型液力偶合器内部气液两相分布规律和转矩特性,以YOX500型限矩型液力偶合器为分析模型,采用流体体积法VOF(Volume of fluid)两相流模型,Realizable k-ε湍流模型和压力隐式算子分裂（Pressure-implicit with splitting of operators, PISO）压力耦合算法对不同充液率、不同工况下的偶合器内部流场进行瞬态模拟。结果表明：随着转速比的降低,偶合器内部环流逐渐由小环流变为大环流,80%充液率的条件下,泵轮叶片吸力面与压力面上的气液两相分布与试验结果基本一致,证明了该方法的有效性。在高转速比时,转矩特性与试验一致,低转速比时误差较大,该方法不再适用。     

限矩型液力偶合器的节能效果

限矩型液力偶合器主要用于带式输送机、刮板输送机、球磨机、砂磨机、破碎机等大惯量载荷设备上。采用限矩型液力偶合器传动,可提高电机的启动能力,降低启动电流持续时间和减小启动电流的平均值;可使电机空载启动,满载时平稳启动,隔振缓冲。多电机驱动时,可实现顺序启动,减小启动电流对电网冲击,并可均衡负荷。     

液力偶合器控制分析

以液力偶合器为研究对象,主要针对限矩型液力偶合器和调速型液力偶合器的控制系统,分析和运用开环控制和闭环控制技术,实现静动态特性优选,有效解决液力偶合器控制系统的瓶颈问题,从而得到液力偶合器控制各模拟参数和状态量,使液力偶合器控制系统性能在运行中更稳定,更符合产品要求。     

国外液力偶合器在中国的应用

中国加入WTO以后，国际贸易额急剧增加，液力偶合器进口额也不断增多。国外限矩型（又称常充型）液力偶合器与各种主机配套进入我国，有很多实例。本文以较为典型的液力偶合器为例，进行介绍与分析，以期对我国液力偶合器技术发展有所促进，有所提高。     

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.