Electromagnetic ultrasonic guided waves inspection of rail base

Ultrasonic nondestructive testing technique has been widely applied to rail inspection. Due to the influence of probe placement and the complex structure of the rail, current devices are limited in the ability of detecting most defects existing in the rail base. In this paper, the electromagnetic acoustic transducer (EMAT) is applied to the inspection of rail base defects. Wave modes in the rail base and their corresponding mode shapes are obtained by applying the finite element analysis (FEA) method. The analysis result implies that pseudo-Rayleigh waves have the potential to detect concerned defects in the frequency range of 300 to 400kHz. To further test the inspection ability of pseudo-Rayleigh waves, an EMAT generating 300kHz pseudo-Rayleigh waves is designed and two artificial defects of different types in a rail base specimen are detected using this EMAT. The experiment result indicates that pseudo-Rayleigh waves are suitable for the inspection of rail base.