高速列车可调阻尼油压减振器的研究

能根据列车运行状况实现阻尼特性的调整是高速列车半主动减振器的基本要求。文章研究设计了一种通过电液比例换向阀改变阻尼力的油压减振器，并对该油压减振器的结构和工作原理及阻尼特性进行研究分析。理论分析和实验研究表明，所设计的电液比例控制变阻尼油压减振器可实现阻尼力的无级调整。     

先导式电液比例溢流阀的动态特性研究

以先导式电液比例溢流阀为研究对象,并结合其工作原理建立仿真模型,对先导式电液比例溢流阀动态特性进行研究分析。通过改变主阀上腔容积和固定阻尼孔R₁和R₂的孔径对溢流阀主阀口进口压力,先导阀口压力动态仿真曲线进行比较与分析,为溢流阀的研究设计和性能优化提供参考依据。     

基于Simulink的电液比例溢流阀频响仿真

研究了基于B型半桥液阻网络的电液比例溢流阀,建立了该阀的动态数学模型,并应用Matlab的仿真软件分析了该阀的频响特性,研究表明阀的入口流量和固定液阻值对电液比例溢流阀的频率响应有比较明显的影响,得到了具有良好频率响应特性的电液比例溢流阀设计参数.     

汽车磁流变减振器阻尼特性理论分析与计算

设计了单输出杆阻尼孔式汽车磁流变减振器,根据牛顿流体理论和磁流变液流变特性,对磁流变减振器的阻尼特性进行了理论分析和计算,探讨了减振器各结构参数对减振器阻尼特性的影响,采用Lord公司的MRF-132AD型磁流变液,计算和分析了磁场强度对阻尼力的影响,以及各种磁场强度下阻尼力与速度的关系.     

车辆悬架磁流变减振器阻尼特性实验研究

磁流变减振器的阻尼力特性是磁流变半主动悬架系统在振动控制中分析和设计的重要依据。基于实验研究磁流变减振器的阻尼特性,分析其阻尼性能的特点,拟合库仑阻尼与电流的关系式,为磁流变半主动悬架的系统控制和应用提供理论支持。     

叶片减振器比例控制阀动态特性仿真与实验

比例控制阀是叶片减振器的核心部件之一,是减振器阻尼力调节的执行部件。介绍了比例控制阀的工作原理,并基于比例控制阀的结构特点,建立了比例控制阀的CFD模型,分析其流场分布,对其动态特性进行分析,确定其流量与开口度及驱动电流的关系,并通过比例控制阀的试验验证了分析结果的正确性,为叶片减振器的阻尼特性分析及阻尼力控制策略奠定了基础。     

汽车磁流变减振器阻尼特性理论计算与试验

从研究的实用性和结构的可行性出发,建立较为精确的磁流变减振器动力学模型是设计控制策略和获得良好控制效果的关键因素之一。根据车辆悬架的各种要求,设计和分析磁流变减振器的各参数对阻尼特性的影响对于现代汽车设计来说是非常必要的。根据汽车减振的要求和磁路设计原则,设计出单输出杆阻尼孔式汽车磁流变减振器。基于流体力学理论和磁流变液流变特性,详细推导出磁流变减振器的阻尼力理论计算模型。对磁流变减振器的阻尼特性进行理论分析和计算,并探讨减振器各结构参数对减振器阻尼特性的影响。最后采用试验测试磁流变减振器的速度特性,得到不同电流输入时阻尼力与速度的关系曲线,试验测试的结果和理论计算基本吻合。采用流体力学理论推导出的磁流变减振器力学模型能为建立减振器控制模型提供可靠的理论指导。     

比例电磁阀内置式CDC减振器设计与验证

设计了一种比例电磁阀内置式连续阻尼可调(Continuously Damping Control, CDC)减振器,分析了其主要结构组成及工作原理,并基于流体力学建立了参数化仿真模型。通过仿真和试验的方法获得了该CDC减振器的示功特性曲线和速度特性曲线,并从2组特性曲线的形态变化来分析了其阻尼特性的可调范围和调节特点。结果表明：仿真和试验结果相对误差小于10%,仿真模型准确有效;该CDC减振器的阻尼力随着激励电流的增大而减小,这种减小趋势的速率随着激励电流的增加先增大后减小;速度特性曲线的斜率在“拐点速度”之前逐渐变大,在“拐点速度”之后基本不变,且随着激励电流的增大而逐渐减小;该CDC减振器在复原行程的阻尼力可调范围为1544～4914 N,压缩行程的阻尼力可调范围为-1415～-1937.7 N。     

回转叶片式磁流变减振器阻尼特性分析

介绍了回转叶片式磁流变减振器的结构和工作原理,基于平板模型得出了其阻尼力和阻尼可调系数的计算公式.对自行研制的回转叶片式磁流变减振器的阻尼可调系数与阻尼孔内流速的关系等进行了理论分析．通过深入分析该型减振器的阻尼特性,为其在车辆悬挂系统半主动控制中的应用奠定了基础．     

小流量工况下比例溢流阀振动问题研究

针对液压系统中,小流量工况下,比例溢流阀引起的回路振动问题,简化和分析了试验回路,并通过对比试验和对比例溢流阀结构及力平衡方程的分析,研究了比例溢流阀动态特性影响因素和小流量状态下振动问题的起因.经过分析,比例溢流阀固定阻尼孔的直径为影响其动态特性的主要因素之一.经过理论推导和试验验证,在溢流阀下面加过度块和阻尼的方法...     

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.     

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.