列车轮对几何参数与缺陷动态测量

轮对是列车运动和受力的主要部件,轮对故障是列车安全运营的一大隐患。对轮对几何参数与缺陷进行快速、准确的测量,可有效降低事故率和维修成本,为轮轨设计与制造提供科学的决策依据,已成为世界各国相关领域的研究重点。本文在简述轮对几何参数检测发展现状的基础上,主要介绍我们近20年来在轮对几何参数与缺陷动态在线检测方面的工作,我们率先提出平行四边形机构定量测量轮对踏面擦伤与圆周磨耗原理,进而提出使用一维激光位移传感器高精度动态测量踏面直径、多线激光测量车轮几何参数与缺陷等方法,研制了几种不同类型的轮对在线测量系统应用于铁路现场。论文最后讨论了轮对检测未来的发展趋势。     

基于弱磁技术的火车轮踏面裂纹检测

针对火车轮踏面易萌生细小裂纹的问题,提出一种无需励磁,利用地磁场磁化的无损检测方法.根据火车轮踏面结构设计探头工装,利用弱磁检测仪器采集车轮踏面磁感应强度信号,分析预制裂纹缺陷的磁异常信号特征,对比不同深度裂纹的磁异常信号幅值,通过傅里叶最小二乘拟合得到缺陷深度的定量算法,根据极值差法与拉依达准则对火车轮踏面进行智能识...     

火车车轮踏面缺陷多通道检测系统的研究

在高速列车运行过程中,车轮作为最主要的承载部件,极易出现踏面擦伤等缺陷测.本文介绍了安装在钢轨上的多通道在线式加速度传感器检测系统,该方法以Cyclone系列FPGA为核心控制模块,完成与后端DSP数字信号处理器间的通信,实现车轮踏面损伤的测量,并对现场采集到的数据进行处理分析.实验结果证明,本系统能够实现对多通道车轮...     

车轮踏面参数智能检测仪校准方法及校准装置的研发

本文介绍了车轮踏面参数智能检测仪校准方法及校准装置的研发。     

25G客车车轮踏面缺陷分析

在役25G特快客车用巴西和马钢的车轮上均出现横向裂纹、剥离和剥落等缺陷。对缺陷车轮进行了分析,认为热裂纹源于马氏体层中的微裂纹;近表层区域的应力状态决定了热裂纹的扩展形态,热裂纹扩展的结果导致剥离、剥落缺陷的出现。     

车轮型面测量及手持式测量仪的研究

本文概述了铁路车轮踏面形状测量技术的现状，对一种手持式测量装置进行了研究，实际使用表明：这种仪器操作简便、精度较高，这种仪器也可用于其它相近磨耗物体的外形测量。     

基于CCD测量车辆轮对轮缘的几何参数

本文介绍了利用CCD传感器获取车辆轮对轮缘轮廓曲线的原理和轮缘几何参数的检测方法.阐述了测控系统装置,给出了实验结果并进行了误差分析.该系统工作稳定可靠,说明了基于CCD测量车辆轮对轮缘几何参数的方法是可行的.     

基于坐标测量机的铁路轮对参数的测量方案

设计了一种基于三坐标测量机的轮对几何参数自动测量装置,对其主要结构和工作原理作了详细分析,并给出来轮对几何参数的计算式。该测量装置结合了三坐标测量机测量精度高和自动测头智能化程度高的特点,可实现工件的自动、批量化检测,它对于解决目前轮对测量手段落后、测量误差大、劳动强度高等问题具有一定的实际意义。     

几何量图像检测技术及其应用

近几年随着光电子和计算机技术的发展,光电转换技术的使用越来越多,文章简单介绍了ＣＣＤ电荷耦合器件和半导体像位置检测元件ＰＳＤ的基本测量原理和一些在工业上的应用实例     

A method of fretting wear reduction in an automatic wheel set gauge change system

The SUW 2000 railway vehicle wheel set with an automatic gauge change system is especially exposed to fatigue wear due to the specific working conditions. Taking into consideration the role which a wheel set has in both vehicle handling on a track and providing safety of railway traffic, the wheel set damage is impermissible. It also applies to the sleeve–axle rotational connection. This article presents research into both finding new and low-cost materials for a slide sleeve in the wheel hub node and looking for cheaper technologies for improving the surface layer of the wheel set under-hub which would eliminate fretting wear. The research was conducted on a simplified physical model of a real connection between a wheel and an axle. The results of the conducted wear tests show that fretting wear can be effectively limited by applying a metallic layer in the form of molybdenum coating. Grease with the addition of molybdenum disulphide can also protect the co-operating surfaces against fretting wear. It also allows for sustaining proper working conditions of frictional pair elements. This solution, however, is onerous due to the limited maintainability of the connection node. The studies carried out show that there is a full possibility of using this solution in real exploitation.     

Ultrasonic evaluation of geometrical and surface parameters of rough defects in solids

Ultrasonic measurements from rough cracks were carried out using both broad-band and narrow-band methods. An analysis is suggested to determine parameters of the crack quantitatively such as size, shape, rms surface roughness, and distribution function of the surface roughness. Ultrasonic measurements of the parameters compare very well with the actual parameters of the defect.     

Effect of physical and geometrical parameters on transverse low-velocity impact response of sandwich panels with a transversely flexible core

The effects of important physical and geometrical parameters on transverse low-velocity impact response of composite sandwich panels have been studied in this paper. Impacts are assumed to occur normally over the top and/or the bottom face sheets, at arbitrary locations and with different impactor masses and initial velocities. For deriving closed-form solutions for the contact force, displacements of the impactor and the panel in the transverse direction, the sandwich panel has been modeled as a discrete three-degrees-of-freedom dynamic system with equivalent masses and springs (SM). The dynamic response of the panel is based on the improved higher-order sandwich plate theory (IHSAPT) and both thick and thin panels have been analyzed. The effects of transverse flexibility of the core, and boundary conditions are considered. Also, the area of the contact patch between the impactor and the panel can be varied as it changes with contact duration. The numerical results of the analysis have been compared either with the available experimental results or with some theoretical results. It is established that the dynamic behavior of the sandwich panel depends on various parameters, such as the aspect ratio and the length-to-thickness ratio of the panel, core thickness, boundary conditions of the panel and impactor parameters like its potential energy, velocity and the location of contact point, etc.     

Quantitative estimation of measurement errors for general technological parameters

Results are presented on the metrological characteristics of multichannel data-acquisition systems (DAS) that perform indirect measurements. General and typical structures are given for such DAS, which are represented by mathematical models for the errors in processing the data in them. An analysis is presented of the dependence of the error on the DAS parameters and input signals.Translated from Izmeritelnaya Tekhnika, No. 10, pp. 16–20, October, 2004.     

成形磨砂轮圆弧廓形关键参数在位检测方法及试验研究

针对成形磨砂轮精密磨削加工中准确高效地检测砂轮形状精度的需求,提出砂轮廓形参数在位检测新方法.首先采用线状激光位移传感器采集砂轮表面微观形貌数据,构建测量矩阵模型,再通过滤波去噪、宏观轮廓线提取、非线性曲线拟合等算法分析处理出砂轮廓形曲率半径和圆度误差检测指标.通过磨削验证试验分析和检测不确定度评定,证明该方法稳定可靠...     

超临界二氧化碳物性参数测量方法综述

对于超临界二氧化碳(S-CO2)物性参数的获取,一般可从美国国家标准与技术研究院(NIST)直接查询,但S-CO2在临界点处物性发生剧烈变化.在实际工业应用中,S-CO2的密度、粘度和热导率这3个方面对与超临界二氧化碳布雷顿循环的研究有着很重要的作用,为了解目前S-CO2物性的测量方法,该文对当前所涉及到的S-CO2基...     

Level set and geodesic active contours based measurement of material removal between serial sections

The measurement of the thickness of material removed between serial sections is a crucial step of three-dimension reconstruction. Geodesic active contours is an efficient method for contour detection of objects on an image. The indents on the SiC/Al composite micrographs are segmented by using level set and geodesic active contours. After getting the contours of the indents, we calculate the distance from the uppermost pixel to the lowermost pixel to get the vertical diagonal length, and calculate the distance from the leftmost pixel to the rightmost pixel to get the horizontal diagonal length of each contour. Then the final length of each diagonal is acquired by averaging the vertical diagonal length and the horizontal diagonal length, respectively. The Vickers’ indenter is made by a square pyramidal-shaped diamond with opposite faces at an angle of 136°, so the thickness of material removed between two serial sections and the length difference of the diagonals on the two serial sections has a definite geometrical relation. Thus the thickness of material removed between two serial sections is acquired using the geometrical relation.     

Sonochemical synthesis of Fe-doped Cu3Se2 nanoparticles: Correlation of the strain and electrical properties for optoelectronics applications

This research presents the effect of different concentrations of iron (Fe) as dopants on the physical properties of the copper selenide (Cu₃Se₂) nanoparticle (NPs). The physical properties of the Cu₃Se₂ NPs were investigated using structural, morphological, and optical analysis. The results revealed that the Fe concentrations change the crystallite size (from ∼8 to 44 nm) and strain (from ∼0.0007 to 0.0030). Fe-doped Cu₃Se₂ NPs showed a higher optical energy band gap in comparison to the un-doped sample (1.80 eV). The films prepared by green binder (ethyl cellulose) indicated that the sample with minimum Fe concentration presents the highest carrier concentration (9.56e+18 cm⁻³) and lowest ideality factor (2.02) amounts. The electrical study shows space charge limited current (SCLC) mechanism in Fe-doped Cu₃Se₂ NPs that is not observed in un-doped sample. Using this mechanism, the highest carrier mobility (16.22 cm⁺²V⁻¹s⁻¹) obtained for sample with the lowest amount of Fe concentrations.     

水声材料声学参数及其声管测量方法

简要阐述了水声材料产品研制过程中水声材料及其声学参数测量的重要意义和存在的问题,详细论述了水声材料声学参数分类及相应的测量方式,归纳了脉冲法、驻波法和行波法声管各自的测量原理和适用的条件,以及声管测量技术的发展趋势,最后总结了通过声管测量水声材料声学参数时,对测量声管和被测量样品的一般要求。     

Mahematically fuzzy summation and optimization of measurement errors in a technological operation

The paper discusses mathematically fuzzy summation of measurement errors in a technological operation on rules that differ from those usually employed for additive or quadratic summation. To optimize the errors, a linear programming method is proposed with control variables in the form of carriers of these errors. As in the mathematically nonfuzzy case, two self-conjugate optimization methods are employed: functional and economic. Paper written on the basis of the report presented at the 10th All-Russia Conference on Measurement State and Problems, which was held at the Bauman Moscow State Technical University in April 2008 (see selection of articles in Measurement Techniques, Nos. 10 and 11 (2008)). Translated from Izmeritel’naya Tekhnika, No. 2, pp. 12–17, February, 2009.