Ultrasonic Tomography for Three-Dimensional Imaging of Internal Rail Flaws: Proof-of-Principle Numerical Simulations

Proof-of-principle numerical simulations demonstrate the technology of ultrasonic tomography for three-dimensional (3-D) imaging of internal rail flaws. New technologies are needed to quantify internal rail flaws so as to ensure increased safety of rail transportation and reduced rail maintenance costs. The technique of ultrasonic tomography was applied to the detection of a 5% head area transverse defect in the rail head. Finite element models of ultrasonic tomographic arrays on a flawed rail were built, followed by an algorithm designed to perform the tomographic imaging of the internal rail flaw in three dimensions. The results showed excellent 3-D imaging performance. The work confirms the potential of ultrasonic tomography for the quantitative verification of internal rail flaws.