基于相似原理的摩擦材料1：5缩比台架及其可比性分析

因试验设备结构、功能不同，导致车用摩擦材料摩擦磨损性能的小样试验结果与台架试验相差较大。为提高小样试验与台架试验的可比性，依据相似原理，并参照现有JFl22型轻轿车1：1惯性台架试验机的参数，研制了JFl22SB型摩擦材料1：5缩比台架摩擦试验机，用于轿车盘式制动器摩擦衬片的缩比试验。介绍了1：5缩比台架摩擦试验机的设计准则、缩比比例、主要参数和结构，并采用同一个试验方法标准SAEJ2681，与1：1台架进行了对比试验，结果表明：二者的试验数据具有良好的一致性和可比性。     

汽车制动衬片1:5缩比试验台的研制与应用

依据相似原理,在1:1台架的基础上,设计并研制1:5缩比试验台,以提高小样试验和台架试验的可比性。详细阐述了1:5缩比试验台的工作原理、结构组成及其技术参数,简述了其控制系统组成及其控制方式。该机结构设计合理的,性能优良,完全符合测试标准要求。为利用小样试验进行摩擦材料研究、摩擦磨损性能的预测与全面评估以及生产质量控制提供了一种新的试验手段,也为汽车制动衬片的摩擦磨损性能测试提供更可靠的小样试验设备。     

汽车摩擦材料惯性缩比试验装置与试验流程研究

为建立具有广泛适用性的摩擦材料惯性缩比试验方法,对惯性缩比试验的试验装置和试验流程进行初步研究,给出惯性缩比试验装置的基本特征以及可用于惯性缩比试验的摩擦盘和摩擦材料样块的具体参数,提出速度和压力缩比系数概念,并在台架试验标准ISO-26867的基础上提出一种适用于惯性缩比试验的建议试验流程。在符合上述基本特征的惯性缩比试验台上进行实验研究,并与同批次摩擦片的台架试验进行对比分析。结果表明,该试验装置执行建议缩比试验流程测得的结果与台架试验可比性较好,证明了所提出试验装置与试验流程的有效性,为摩擦材料惯性试验方法的建立提供了借鉴。     

汽车摩擦材料缩比Krauss摩擦试验机的研制及比较性评价

为了提高小样试验工况的可模拟性,降低试验成本,提高试验效率,以Krauss试验机为原型,根据相似原理,应用量纲分析法推导缩比Krauss试验机的基本参数,研制了一种缩小比例的Krauss试验机。选用PVW-3212试验规程,选取同一批次汽车制动衬片进行试验研究,通过对摩擦因数、试验温度和试验周期等指标进行比较。结果表明,全程平均摩擦因数较接近,摩擦因数最大值和最小值出现的阶段和制动次序均相同,全程平均温度具有很好的线性相关性。执行相同PVW-3212试验规程的情况下,在制动初始和制动解除阶段,缩比Krauss试验机压力响应较快,全尺寸Krauss试验机压力响应较慢,缩比试验制动结束时间提前约100 ms,每次试验成本约为全尺寸Krauss试验机的29.67%。缩比Krauss试验机与全尺寸Krauss试验机具有较好的一致性和可比性,证明了该缩比Krauss试验机的可靠性,为摩擦材料的测试提供了一种新的试验装置。     

离合器摩擦材料摩擦磨损性能小样试验的设计

根据定速式摩擦试验机GB/5763-98国家试验标准和实际情况,设计了适合离合器摩擦材料摩擦磨损性能小样试验的设备,给出了试验机结构简图和夹具图;通过正交试验方法,得出离合器摩擦材料摩擦磨损性能试验中载荷、转速和温度三个影响因素的最优水平值,设计了具体的摩擦学小样试验的试验方法.     

JF151型定速摩擦试验机的研制与应用

在JF150型定速摩擦试验机的基础上,设计并研制JF151型定速摩擦试验机。采用重力砝码式标定,使标定值更准确。风机下置,提高风机的使用寿命。增加水箱和卸载手柄,减轻了操作者的劳动强度。采用计算机进行控制和检测,控制精度更高,试验数据更准确,整体结构紧凑,操作方便。详细阐述了JF151型定速摩擦试验机的工作原理、结构组成及其技术参数,简述了其控制系统组成及其控制方式。该机结构设计合理的,性能优良,完全符合测试标准要求。     

不同摩擦副在MM3000型试验机和TM-3型台架机上的对比试验研究

在MM3000型试验机和TM-3型台架机上,在0.40-0.50MP制动压力、80-200km/h制动速度下,对比了不同摩擦副干态工况条件的平均摩擦系数与磨损量。结果表明:克诺尔铜基摩擦材料配对钢制动盘的摩擦副在MM3000试验机上的摩擦系数高于在TM-3台架机上的摩擦系数。相反,克诺尔铜基摩擦材料和金属陶瓷摩擦材料配对碳陶制动盘的摩擦副在MM3000试验机上的摩擦系数都低于在TM-3台架机上的摩擦系数。另外,不论是MM3000试验机,还是TM-3台架机,克诺尔铜基摩擦材料配对碳陶制动盘时的磨损量最大,克诺尔铜基摩擦材料配对钢制动盘时的磨损量居中,金属陶瓷摩擦材料配对碳陶制动盘时的磨损量最小。     

JF120摩擦材料缩比试验台设计理念和基本结构

缩比试验是以相似理论为依据的一种试验方法,在产品和生产流程的开发中有广泛的应用。汽车摩擦材料的基础开发需要一种能够模拟实际工况的缩比试验设备,提高开发效率和降低测试成本。介绍了JF120缩比试验台设计理念和基本结构,和依据缩比率提出的缩比试验台的技术参数。     

ABFT-1型轿车轮毂轴承摩擦力矩试验机

根据轿车轮毂轴承生产厂家及其用户对轮毂轴承摩擦力矩测量的要求,研制了ABFT-1型轿车轮毂轴承摩擦力矩试验机,给出了试验机工作的基本原理和加载机构的设计方法,介绍了控制系统和人机操作界面。     

摩擦材料研发过程中摩擦对偶对摩擦材料性能测试结果的影响分析

通过采集相同摩擦材料在台架试验机上使用不同公司生产的制动对偶即制动盘进行对比测试的测试结果和采集用相同的摩擦材料在不同的定速试验机以及在同一台定速试验机上进行间隔测试和连续测试的对比测试结果,分析探讨摩擦对偶状态对摩擦材料性能测试结果重复性和再现性的影响,并对摩擦材料配方研发过程中测试摩擦材料性能时使用摩擦对偶提出建议性方案。     

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.     

Limits of topographic measurement by the scanning tunnelling and atomic force microscopes

Parameters describing the topographic character of a surface (height, surface wavelength, slope and curvature) can be derived from equivalent sinusoidal profiles. The response of a surface-measuring instrument may be modelled in terms of instrument parameters such as stylus radius, and scanning range and resolution. The performance of the instrument may then be mapped as a zone in amplitude-wavelength (AW) space to show the sinusoidal profiles it is capable of measuring. In a first-order analysis the STM and AFM are considered as equivalent to contact-stylus instruments with a notional stylus radius equal to the tip radius plus the gap. Comparisons between different instruments and types of instrument are readily made by mapping in AW space. The error arising from convolution of the sinusoidal profile with that of the finite tip may be quantified and plotted as contours in AW space.