浅谈检定中的滑板式汽车侧滑检验台示值误差的调整

滑板式汽车侧滑检验台（以下简称侧滑台）是测量汽车车轮在直线行驶过程中,车轮外倾角和前束的匹配情况,具体用侧滑量来表征。侧滑量是指汽车在没有外加转向力的条件下,低速直线行驶通过检验台时,滑板向内或向外的横向位移量与滑板的纵向长度之比值,侧滑量以m／km表示。根据中华人民共和国国家计量检定规程JJG 908-96《滑板式汽车侧滑检验台》中规定侧滑台示值误差不超过±0．2m／km。     

滑板式汽车侧滑检验台示值误差测量结果的不确定度评定

一、问题的提出 滑板式汽车侧滑检验台(以下简称侧滑台)是用于动态测量汽车前轮定位值(前轮外倾角与前束的匹配程度)的汽车性能计量检测设备,根据JJG908-96《滑板式汽车侧滑检验台》国家计量检定规程规定:侧滑台的示值误差不得超过±0.2m/km;检定示值误差的方法是采用百分表(如图所示)。     

滑板式汽车侧滑检验台示值误差的测量结果不确定度

1.测量方法 根据检定规程JJG908-96《滑板式汽车侧滑检验台》,通过用百分表测量滑板的横向位移量来测量侧滑台的示值误差。     

滑板式汽车侧滑检验台示值误差测量结果的不确定度评定

本文依据JJG908-1996滑板式汽车侧滑检验台检定规程和JJF1059-1999测量不确定度评定与表示,对滑板式汽车侧滑检验台示值误差测量结果进行了不确定度的评定,通过阐述测量过程中产生的各分量对测量结果的影响,得到了测量结果的扩展不确定度。     

滑板式汽车侧滑检验台示值误差的不确定度

1 测量方法 依据JJG908-996《滑板式汽车侧滑检验 台》规程规定,滑板式汽车侧滑检验台(以下 简称侧滑台)的示值误差是采用百分表作为标准 器进行测量的。用磁性表座将百分表固定在基座 上,挡位工具固定在滑板上,百分表测杆轴线与 滑板移动方向一致,调整好仪表及百分表零位, 用微动工具缓缓推动滑板,当侧滑台示值分别为 3m/km、5m/km、7m/km时,分别读取百分表 示值。左、右滑板均应测量,每一测量点重复测 量3次,取3次读数的平均值作为该点测得值。     

JJG908-2009《汽车侧滑检验台》检定规程修订解读

<正>一、修订背景JJG908-1996《滑板式汽车侧滑检验台》检定规程(以下简称"旧规程")于1996年6月28日经国家技术监督局批准发布,并自1996年12月1日起施行。旧规程颁布10余年     

CHJ型侧滑检验台检定仪的误差分析

本文对ＣＨＪ型侧滑检验台检定仪测量滑板位移量和动作力的误差进行了分析。     

汽车侧滑检验台测量值的扩展不确定度评定

为了保证汽车侧滑检验台检测数据的准确可靠,本文对汽车侧滑检验台测量值的不确定度进行了分析、评定,供同行们共同探讨。     

侧滑检验台全自动检定装置的不确定度验证方法

侧滑检验台全自动检定装置是用于检定汽车侧滑检验台的标准器。本文针对原有的汽车侧滑检验台检定装置主标准器的不确定度验证方法,同时根据新研制的侧滑检验台全自动检定装置的工作特点,提出了一种将数显大量程千分表作为更高级计量标准,采用传递比较法的不确定度验证方法,仅供参考。     

一种多功能磁性表座的制作与应用

磁性表座是汽车侧滑检验台检定装置中的重要附件。本文针对目前汽车侧滑检验台检定装置附件磁性表座的吸附效果差及使用功能单一等问题,制作出一种多功能的电磁表座,它具有吸附效果好,可替代汽车侧滑检验台检定装置中拉力计的作用等特点。供同行们参考。     

完善对滚筒反力式制动检验台的“检定”

分析了同一辆机动车在不同型号的制动台上由相同检验员检测,会得到不同的结果的原因。通过"机械"或"电子"方法对滚筒反力式制动检验台进行"模拟制动力"加载,经实验验证,是对滚筒反力式制动检验台原"静态检定"工作的一种有效、可靠的"完善"和"弥补"。通过"模拟制动力"加载试验,能发现滚筒反力式制动检验台或计算机联网中存在的问题。提出滚筒反力式汽车制动检验台在生产、使用中应注意的问题。     

汽车发动机综合参数测试仪校准方法研究

针对汽车发动机综合参数测试仪,介绍了一种对其实现现场校准的装置和现场校准的方法。经现场校准实验,给以解决该综合参数测试仪的流量、压力和温度的现场溯源问题,为汽车发动机的研发和生产提供有力的技术支撑和计量保障。     

二次加工脆性的试验方法及其应用

针对高强度汽车用钢板成形后出现的脆性现象,从脆性产生的原因和脆性测定的基本原理出发,讨论了测定其二次加工脆性的试验方法和评判指标,以及影响其测定结果的装置方面因素;相应开发了一种试验装置,进行了相关的试验,试验结果表明,该测试装置可以较好地用来测定薄钢板的二次加工脆性。     

A shear-deformable two-layer plate element with interlayer slip

A new finite element for two-layer plates with built-in interlayer slip is developed. The new plate element is based on a new plate theory formulated using a new variational principle due to Reissner. The accuracy of the new element is investigated by applying it to the problem of a two-layer plate with a linear slip law in cylindrical bending for which an exact elasticity solution exists. The comparison of the inplane response for several different values of interlayer shear stiffness and layer thickness ratios shows that the new element gives accurate results. The cylindrical bending of a two-layer plate with bilinear interlayer slip law is investigated with the new element and the results obtained are compared with a plane strain analysis. Good agreement is obtained for in-plane normal stresses and displacements. To further assess the simulation capabilities of the proposed element, a rectangular plate under concentrated load is analysed and the growth of slip failure regions is shown.     

高成型性细晶粒510MPa级热轧汽车板的开发和应用研究

对高成型性细晶粒510MPa级的热轧汽车板进行了开发和应用研究,文中通过轧制以及有限元分析和热模拟试验,提出表面产生混晶和拉长变形晶粒的原因和避免措施.以及CSP线生产这类高强度高成形板材的工艺.结果表明:采用深过冷轧制可以有效避免表面的混晶和微裂纹,改善冷弯成形性,以此思想作指导设计的合金成分和制定的CSP线轧制工艺,所生产510MPa的汽车热轧板,具有良好的强度和延性匹配,可以冲压成形状复杂的发动机横梁.     

A study aimed at determining and understanding the fracture behaviour of an Al–Li–Cu–Mg–Zr alloy 8090

The S-L fracture toughness of aluminium–lithium based alloys is generally poor and this has limited their applicability, particularly in aerospace where good damage tolerance is required. The low S-L toughness has been attributed variously to grain boundary precipitation, planar slip and lithium segregation. This work examined the S-L fracture behaviour of an 8090 Al–Li-based alloy in 34–45mm plate. The results confirmed that the S-L fracture toughness decreases from the centre to the surface of plate material and increases with double ageing. Fracture is principally intergranular, with both ductile and brittle components occurring, but some transgranular fracture also occurs and this produces steps in the fracture plane. Changes in the relative proportions of brittle and ductile intergranular fracture, as well as in the amount of transgranular fracture, accompany the changes in toughness. However, the decrease in fracture toughness across the plate is accompanied principally by an increase in the relative proportion of brittle intergranular fracture, while the toughening produced by double ageing is accompanied principally by an increase in the amount of transgranular fracture. Evidence of coarse slip, indicative of slip planarity, was seen from slip steps and dislocation structures. However, planar slip was seen only towards the centre of the plate and not towards the surface. The level of planar slip was not reduced markedly by double ageing. Texture varied with position across the plate. There were also a larger number of low angle boundaries towards the centre of the plate than towards the surface. The hardness did not change across the plate. The results could not be explained fully in terms of either the grain boundary precipitate theory or the planar slip model, but were generally consistent with the lithium segregation model. However, the basic tenet of this model is that the level of embrittlement is influenced by the grain boundary structure, and the results did not indicate a substantial difference between the boundaries that failed in a ductile manner and those which failed by brittle fracture. This suggests that the factors which affect lithium segregation may be more complex than originally envisaged.     

高成型性细晶粒510MPa级热轧汽车板的开发和应用研究

对高成型性细晶粒510MPa级的热轧汽车板进行了开发和应用研究,文中通过轧制以及有限元分析和热模拟试验,提出表面产生混晶和拉长变形晶粒的原因和避免措施.以及CSP线生产这类高强度高成形板材的工艺.结果表明:采用深过冷轧制可以有效避免表面的混晶和微裂纹,改善冷弯成形性,以此思想作指导设计的合金成分和制定的CSP线轧制工艺,所生产510MPa的汽车热轧板,具有良好的强度和延性匹配,可以冲压成形状复杂的发动机横梁.     

Shear flow over a particulate or fibrous plate

Simple shear flow over a porous plate consisting of a planar array of particles is studied as a model of flow over a membrane. The main objective is to compute the slip velocity defined with reference to the velocity profile far above the plate, and the drift velocity induced by the shear flow underneath the plate. The difference between these two velocities is shown to be proportional to the thickness of the plate. When the geometry of the particle array is anisotropic, the directions of the slip and drift velocity are generally different from the direction of the overpassing shear flow. An integral formulation is developed to describe flow over a plate consisting of a periodic lattice of particles with arbitrary shape, and integral representations for the velocity and pressure are developed in terms of the doubly-periodic Green's function of three-dimensional Stokes flow. Based on the integral representation, asymptotic expressions for the slip and drift velocity are derived to describe the limit where the particle size is small compared to the inter-particle separation, and numerical results are presented for spherical and spheroidal particles of arbitrary size. The asymptotic results are found to be accurate over an extended range of particle sizes. To study the limit of small plate porosity, the available solution for shear flow over a plane wall with a circular orifice is used to describe flow over a plate with a homogeneous distribution of circular perforations, and expressions for the slip and drift velocity are derived. Corresponding results are presented for axial and transverse shear now over a periodic array of cylinders arranged distributed in a plane. Streamline pattern illustrations confirm that a negative drift velocity is due to the onset of eddies between closely-spaced particles.     

Development of secondary plastic strips near tensile cracks in the plate

We suggest a method for the solution of the elastoplastic problem of biaxial tension-compression of a thin cracked plate under the assumption that plastic strains at each tip of the crack are localized along three slip lines. The plastic zone is simulated by three inclined slip strips at the tips of the crack. It is assumed that the material of the plate is absolutely elastoplastic and the yield criterion is satisfied along the slip lines. The strips lying on the continuation of the crack are simulated by segments of discontinuity of normal stresses, while the other strips are simulated by segments of discontinuity of tangential stresses Thus, the elastoplastic problem under consideration is reduced to the boundary-value problem of the linear theory of elasticity for a body weakened by branched cuts with unknown lengths and orientations of side branches. These parameters are determined in the process of numerical solution of the problem by the method of singular integral equations. Numerical results are presented for the semiinfinite plane with edge crack and under the conditions of uniform tension at infinity. We present numerical values of some parameters of nonlinear fracture mechanics, such as crack tip opening displacement and lengths and angles of inclination of plastic strips, for various combinations of the components of external load.Karpenko Physicomechanical Institute, Ukrainian Academy of Sciences, L'viv. Translated from Fiziko-Khimicheskaya Mekhanika Materialov, Vol. 31, No. 2, pp. 7–13, March – April, 1995.