Advances in fatigue crack growth monitoring of R260 rail steel using acoustic emission monitoring

This paper presents recent advances in our understanding of the relationship between fatigue crack growth rate and the corresponding acoustic emission activity in R260 steel used in manufacturing of plain rails. The acoustic emission (AE) monitoring technique offers the potential to enhance existing structural health evaluation techniques based on conventional inspection methods currently used in the rail industry. AE can provide information regarding the structural health of rails without requiring continuous access to the rail network. In this way the disruption on normal railway operations arising from structural health evaluation intervention can be minimised, maximising the capacity and availability of already busy railway routes. The use of AE monitoring to locate propagating fatigue cracks has been widely reported. The present work focuses particularly on the monitoring of crack growth behaviour and evaluation of its severity. This is achieved by simulating actual fatigue conditions experienced by rails under loading, and subsequent analysis of the AE signals generated. The results discussed in the present study show a clear change in signal response with increasing crack length, particularly with respect to the AE energy. The changes identified in the AE activity generated confirm the potential of AE as an effective technique for the enhancement of structural health monitoring (SHM) for monitoring rails.