RAAI – Whole Life Rail Axle Assessment and Improvement Using Ultrasonic Phased array and Corrosion Inspection Systems

The project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 674231.

The overall objective of the RAAI project is to develop novel NDT solutions for the corrosion assessment and crack detection as well as reliability software for high-cycle variable amplitude corrosion fatigue of rail axles. Currently, the most sensitive non-destructive testing methods for inspection of rail axles are surface inspection methods designed for crack detection (such as MPI, eddy current and ACFM) and these do not typically attempt to measure corrosion. Besides current trend is that axles are withdrawn from service long before their design lives because of suspected corrosion developed on the axle surface. The decision to withdraw from service is taken without the full knowledge of the way in which the failure will result from corrosion, as this requires a crack to initiate and the mechanism for this is unknown.

RAAI aims to develop two novel methods:

  1. corrosion assessment
  2. phased array ultrasonic.

The first method assesses the effect of corrosion on high-cycle fatigued component such as the axle and evaluates its remnant life thereby improving the sentencing of corroded axles. The second method is specifically for hollow axles of high speed trains and aims to improve the speed of the inspection (by 75%) and improve crack detection reliability (almost 100% with a crack of 2-3 mm depth) without dismantling the wheel-set and with minimum time of inspection.