Numerical characterisation of guided wave scattering due to welds in rails

Abstract

The analysis of travelling waves in elastic waveguides with complex cross-sections, such as train rails, can only conveniently be performed numerically. The semi-analytical finite element (SAFE) method has become a popular tool for performing such analyses. This paper employs a hybrid SAFE-3D method to investigate the scattering of guided waves interacting with discontinuities, such as welds, in continuous welded train rails. The aim of the analysis is to predict transmission and reflection coefficients for a given incident wave and known discontinuity parameters. This characterisation is useful for predicting the long-range transmission characteristics of transducers in NDT and monitoring systems, such as the rail break alarm system developed by the Institute for Maritime Technology (IMT) and the Council for Scientific and Industrial Research (CSIR). The numerical model can also be used to estimate welded sections properties from experimental measurements using a scanning laser vibrometer.