Influence of axle–wheel interface on ultrasonic testing of fatigue cracks in wheelset

Abstract

For the ultrasonic testing at the wheel seat of railway axles, quantitative investigation of the reflection and transmission phenomena at the axle-wheel interface is important. This paper describes the influence of the axle-wheel interface on the ultrasonic testing of a fatigue crack in a wheelset by applying the spring interface model. The normal and tangential stiffnesses were identified experimentally for an as-manufactured wheelset at the normal incidence, and the reflection coefficient for the shear-wave oblique incidence was calculated. A parametric study was performed to clarify the influence of these interfacial stiffnesses on the incident-angle dependence of the reflection coefficient. The calculated reflection coefficient at the incident angle of 45° qualitatively explained the relative echo-height decrease due to the presence of a wheel observed experimentally for a wheelset in fatigue loading by rotating bending. The quantitative difference between the experimental and calculated results was considered to be due to the reduction of the effective interference of shrink fit by the wear at the axle-wheel interface during the fatigue loading as well as by the applied bending moment. For the estimated relative echo-height decrease to agree with the experimental results, the interfacial stiffnesses were found to be smaller than the values identified for the as-manufactured wheelset by a factor of 0.5-0.7.

Nonlinear output frequency response functions: A new evaluation approach and applications to railway and manufacturing systems’ condition monitoring

“…The quality of train wheels is significant to the safety of high speed trains [31,32]. With the increase of the working time of train wheels, fatigue damage will accumulate and grow.…”

<b>Evaluation of Influence of Reflection Point Shift on Axle Surface in Ultrasonic Flaw Detection</b>

“…If this axlewheel interface is treated as a perfect bonding surface, no reflection waves occur at the interface and the reflection behavior of ultrasonic waves cannot be expressed. Therefore, we applied a spring interface [4][5][6] to the axle-wheel interface, and in this manner, the sound beam displacement at the spring interface was investigated. Here we investigated a periodically cracked interface [7] shown in Fig.…”

“…When shear waves are incident on the spring interface with an angle of η 1 , the phase shift φ of the reflected waves is obtained numerically by solving equations between stress and strain at the interface [6]. By regarding ∂φ/∂h in (1) as Δφ/Δh (note: here Δ means increment), the relationship between the incident angle η 1 and the normalized sound beam displacement Δ/λ is calculated numerically by Δh and Δφ.…”

Quantitative Evaluation of the Flaw Echo of Railway Axles in Consideration of Contact Pressure with a Wheel

“…We assumed that the flaw echoes at stage V were obtained by the free surface reflection with R T = 1. In this assumption, the shear wave reflection coefficient R T was obtained by the ratio of each echo height at stages I to IV to that of stage V. Consequently, the normal stiffness K N was calculated by the equation for the oblique incidence of shear wave with an angle of 45˚ [6]:…”