基于ADAMS软件的发动机右悬置总成优化设计

运用MSC Adams/view建立汽车发动机悬置系统多体动力学模型,对发动机悬置系统进行匹配设计,以满足频率合理分布、模态振型解藕、限位等诸多设计要求.通过对发动机右悬置刚度的优化,改善了发动机悬置系统的隔振性能,降低了整车怠速振动,并进行了试验验证.     

客车转向系统怠速振动研究与优化

针对某款新研制的客车在怠速工况下方向盘抖动过大的现象,用传递路径分析的方法分别对发动机的悬置隔振率、转向系统的支架振动及转向系统的模态进行了分析,找到产生这种现象的原因在于转向系统的一阶纵向弯曲模态和发动机怠速开空调时的转速激励频率相近,从而引起方向盘较大在振动。在此基础上,提出了转向系统的模态避频,实施了转向系统结构加强、转向系统灵敏度分析及优化两个方案。对优化后的转向系统进行振动测试,发现优化后的转向系统振动明显减小,达到了减振的目的。     

发动机悬置隔振性能对车内振动的影响

通过对某车型车内振动进行测试,发现低转速1200～1400r/min时座椅异常抖动。分析发现是发动机悬置隔振性能不良引起,通过对发动机悬置隔振性能进行优化,消除了座椅的异常抖动问题。     

发动机悬置系统怠速隔振优化及工程应用

根据隔振理论以及发动机振动评价指标,借助Adams和Matlab软件分析了发动机悬置系统的固有频率和固有振型。通过试验测得某重型卡车的发动机悬置系统怠速隔振前后的加速度信号。根据试验数据分析了发动机悬置系统怠速振动特性,根据分析结果对发动机悬置的刚度进行优化,并对优化后的悬置系统进行试验测试,通过对优化前后的试验数据的对比分析,得出了优化后的悬置系统可以解决某重型卡车发动机悬置系统怠速隔振差的问题。     

发动机悬置系统的初步设计

引起汽车振动的两大主要振源:一个是发动机产生的有规律振动激励;另一个是路面产生的随机振动激励。通过优化设计动力总成的悬置系统;不但可以隔振动力总成的小振幅,中、高频率振动传到车身;同时,也能隔振车身的大幅度,低频率振动传到动力总成。根据发动机、变速箱、离合器及其它零件的惯量参数,进行计算动力总成的惯量参数;然后根据动力总成的惯量参数,进行优化设计各个悬置位置和刚度,使悬置系统达到初步良好的模态。最后,通过matlab软件分析,将悬置系统模态进一步的优化。     

基于ArtemiS suit分析研究某微卡怠速抖动问题

对某微卡怠速时车身、方向盘、座椅出现严重抖动及驾驶室内轰鸣声问题进行分析与测试,得出其主要原因是右悬置隔振性能水平偏低,经优化悬置系统后,驾驶室内抖动得到明显改善,驾驶室内轰鸣声消除.     

汽车起重机发动机悬置系统的振动测试与优化

针对25 t汽车起重机出现的发动机怠速时振动过大、驾驶室有低频噪声的问题,进行了NVH测试,了解其各工况下振动与噪声水平。并利用ADAMS以悬置系统的刚度和安装角度为变量进行设计优化,改善了悬置系统的隔振性能。通过整车试验,验证了设计改进的有效性和合理性。     

叉车发动机悬置系统优化设计

针对某7t叉车配装五十铃6BG1型发动机存在怠速振动过大问题,对原车的悬置系统隔振效果进行测试。结合测试数据和动力总成已知参数,对悬置系统的解耦率、固有频率及相应的能量分布等进行分析,通过Adamas软件对悬置系统参数进行优化,调整发动机悬置系统刚度,以改善怠速时振动过大问题。     

汽车动力总成悬置系统隔振性能仿真方法

针对动力总成悬置系统隔振性能的优劣影响整车的NVH特性,应用隔振原理,给出了由加速度均方根值定义的系统隔振传递率表达式;基于双层隔振机理,分别建立了动力总成6自由度悬置模型和包括车架的12自由度整车模型,并通过仿真分析比较了两种模型的固有特性和频域响应;在怠速工况下研究了悬置软垫处的加速度响应;最终获得各悬置点的隔振传递率曲线。研究结果表明,整车模型能够反应悬置系统的振动特性及其隔振传递率。     

商用车怠速车内振动优化研究

针对某商用车怠速车内振动大且劣于竞品车的问题,通过实车测试排查,主要原因为动力总成悬置隔振性能较差。建立悬置系统模型,采用多目标优化方法,以系统固有频率、各方向模态解耦率为目标,以悬置软垫三向刚度为变量,结合供应商制造能力,获得了两组满足优化目标且工程上可实现的悬置软垫刚度组合。通过实车对比验证,最终选取了隔振性能最优的方案,优化后,怠速车内振动改善61%,与竞品车相当,达到优化目标。     

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.