Quantitative evaluation of the rotational stiffness of rail cracks based on the reflection of guided waves

Abstract

Abstract This paper proposes an approach to identify the equivalent rotational stiffness of rail cracks based on the reflection of guided waves. The identified rotational stiffness can be adopted to detect the crack and evaluate the safety of the rail. The quasi-bending guided waves propagating in the rail head and web are found and chosen as the detecting guided waves. Considering these guided waves, the relationship between the dynamic parameters of cracks and the power reflection coefficients are deduced theoretically. Cracks are modelled and their rotational stiffness concerning geometric parameters is evaluated. Simulation results indicate that the depth and width of cracks result in a significant decrease of rotational stiffness. Field experiments showed that discontinuities over a long distance can be detected by the selected guided waves in the rail head and web with relative errors less than 1 per cent in 100 metres. And artificial cracks were made to validate the proposed method for rail crack evaluation.