Identification of track irregularity by frequency-domain transfer function

초록

An algorithm for identifying track irregularities along the railway is presented. A baseline frequency-domain transfer function is assumed to be defined at the intact condition between the measured track geometry of the ground displacement and the acceleration measured at a location in a train. The pre-defined transfer function at the intact condition is used inversely to predict track geometry in time with the currently measured acceleration at the same location in a train. The predicted track geometry is compared in time with that of the baseline values at the intact condition. The difference between them is calculated as an error in time and used to identify the track irregularities. An irregularity index is proposed as the ratio between the moving variance of the error at the current inspection and that at the intact condition. A numerical simulation study has been carried out with a train model to examine the presented algorithm. In the analysis for the simulation, the track geometry has been considered as the displacement boundary condition varying in time. The effects of measurement noise on the identification results are also evaluated statistically.