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钢轨纵向应力是铁路安全与维修中一个突出的问题。日常及季节性的温度变化使无缝钢轨产生很高的纵向应力(LRS)。一旦钢轨中出现过大的纵向拉应力,会导致钢轨绝缘连接板及其他钢轨扣件出现疲劳。当出现过大的纵向压应力时,可能引起胀轨,该问题已经成为铁路行业进行安全方面研究的重点。此项研究的目的是为铁路企业在需要的地点提供对钢轨纵向应力进行检测的能力,以便采取合理有效的预防性维修。目前正在内布拉斯加-林肯大学(UNL)进行的研究,由美国联邦铁路局(FRA)提供支持,重点是利用超声波对钢轨纵向应力进行检测*。超声波速度与固体中应力之间的关系,也被称作是声电效应,是此次研究的基础。基础开发工作在内布拉斯加-林肯大学的试验室及有一小段轨道的所谓“工地试验室”内进行。试验室内开发的测量技术被运用到实际现场当中。当前正在将超声波检测数据与安装在钢轨上的应力模块检测的数据直接进行比较。*这些最新的技术,有利于通过移动平台完成钢轨纵向应力的检测。
Rail longitudinal stress is a prominent issue in railway safety and maintenance. Daily and seasonal temperature changes cause high longitudinal stress (LRS) in seamless rails. In the event of excessive longitudinal tensile stresses in the rail, fatigue may occur on the rail insulation and other rail fasteners. When there is excessive longitudinal compressive stress, it may lead to inflation, which has become the focus of safety research in the railway industry. The purpose of this study is to provide railway companies with the ability to detect longitudinal rail stress wherever needed in order to take reasonable and effective preventive maintenance. Research currently being conducted at the University of Nebraska-Lincoln (UNL), supported by the U.S. Federal Railroad Administration (FRA), focuses on the detection of rail longitudinal stresses using ultrasonic waves *. The relationship between ultrasonic velocity and stress in solids, also known as acousto-electric effect, is the basis of this study. Fundamental development work is carried out in the laboratory of the University of Nebraska-Lincoln and the so-called “site laboratory” with a short track. Measurement techniques developed in the laboratory are applied to the actual scene. Ultrasonic test data is currently being compared directly with the data measured by the stress modules mounted on the rails. * These latest technologies are conducive to the detection of rail longitudinal stress through the mobile platform.