The structural health condition monitoring of rail steel using acoustic emission techniques

This paper discusses the work towards the development of a sound methodology for the application of acoustic emission techniques for detecting and monitoring crack growth in rail steels. At the moment rails that are found to be damaged on the network are not immediately replaced. Instead a speed restriction is imposed and affected rails are clamped with special fish-plates until they are replaced, usually after a period of a few days. Unfortunately damaged rails prior to their replacement cannot be reliably assessed for further crack growth with any of the conventional non-destructive evaluation techniques (e.g. ultrasonic) and this is the reason that a speed restriction is imposed. Acoustic emission techniques could potentially be applied for the detection as well as continuous monitoring of further crack growth therefore removing the need of imposing strict speed restrictions which can be as low as 20MPH (32km/h). In order to validate the potential of the AE technique tests are carried out under laboratory conditions on three and four-point bending samples. Various signal processing methods will be examined using AEWin and Noesis software supplied by PAC and Envirocoustics respectively. (2012) by the British Institute of Non-Destructive Testing. All rights reserved.