Construction of Metro Rail Weld Irregularity Spectrum and Its Application to the Analysis of Dynamic Wheel–Rail Interaction

Rail weld irregularities (RWIs) significantly influence the dynamic wheel–rail interaction. Evaluating and controlling these irregularities is essential for ensuring operational safety. In this study, the characteristics of RWIs measured on more than ten metro lines were analyzed, and the power spectral density of the RWIs based on the measurement results was established. Based on the spectrum, a simulation method for RWIs was presented to obtain a realistic RWI with information on wavelengths and amplitudes. A dynamic model based on the vehicle–track coupled dynamics theory was established and verified using the measured axle box acceleration. The influence of the RWIs on the dynamic wheel–rail interaction was investigated using the RWIs as inputs for the dynamic model. The effectiveness of the RWI simulation method was verified by comparing the responses induced by the measured, formulaic, and simulated RWIs. Finally, a method for determining the safety limit of RWI based on the response distribution and reliability theory was proposed. The safety reliability of the four types of RWI with complex wave was analyzed using the proposed method. These results are expected to provide guidelines for maintaining RWI in metro lines.