EDDY CURRENT TESTING, A SOLUTION TO DETECTING ROLLING CONTACT FATIGUE IN RAIL?

This paper details work carried out into producing a practical solution to detecting rolling contact fatigue in rail using the eddy current testing method. An example of one application in the aerospace industry is used to illustrate how eddy current testing has been used in maintaining safety in the transportation industry. An outline of the theory of eddy current testing is given. Eddy current and ultrasonic testing are largely complementary; here they are compared and contrasted (including details of each method's advantages and disadvantages). A typical eddy current probe element covers at most 25 mm width but more typically 1 to 2 mm. To cover the rail head multiple probes are generally used with multiplexed instrumentation. This leads to complex data and large test units. In order to improve the practicality of applying eddy current testing Hocking NDT Ltd have developed the WideScan Rail probe. This is a single probe that is capable of detecting orientated defects in one pass of the rail head and of producing a signal output that is related to the surface length and depth (size) of the flaw. The active face of the probe can easily be contoured to suit different rail heads and indeed could be shaped to suit rolling stock applications. Data are presented of test results achieved with the WideScan Rail probe demonstrating sensitivity to flaws (both natural and artificial). The WideScan Rail probe will be characterized using artificial flaws of different sizes, orientation and probe to rail clearance necessary for practical application. This will be used to determine sensitivity levels that may be achieved using this probe. Modern eddy current instrumentation has led to the availability of high performance lightweight flaw detectors. These may be used with the WideScan Rail probe and a trolley, for rapid manual inspection, offering advantages over the established ultrasonic rail inspection methods. The WideScan Rail probe could be train mounted for high speed automatic inspection and may also be used for detecting surface breaking flaws in rolling stock (e.g. wheels and axles). For the covering abstract see ITRD E122683.

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  • Corporate Authors:

    ENGINEERING TECHNICS PRESS

    46 CLUNY GARDENS
    EDINBURGH,   United Kingdom  EH10 6BN
  • Authors:
    • HANSEN, J
    • CALVERT, J
  • Publication Date: 2002

Language

  • English

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Filing Info

  • Accession Number: 00982693
  • Record Type: Publication
  • Source Agency: Transport Research Laboratory
  • ISBN: 0-947644-49-0
  • Files: ITRD
  • Created Date: Dec 2 2004 12:00AM