Analysis of the Deterioration of Harmonic Local Irregularity on Locomotive Wheel-Rail Vertical Force
By the MATLAB software the article simulated the local irregularity, the new harmonic excitation superimposed on the initial harmonic to simulate track settlement deterioration, the new uplift excitation superimposed on the initial harmonic to simulate track raised deterioration, as the locomotive model external excitation, using the SIMPACK multi-body dynamics simulation software to analyze the influences of the deterioration of harmonic local irregularity on locomotive wheel-rail vertical force, on the basis of the locomotive wheel-rail interaction dynamics index by the locomotive vehicle dynamics theory. The simulation results show that when the deterioration of harmonic local irregularity occurs, even if the amplitude of deterioration is small, which will cause serious deterioration of wheel-rail dynamic response and strong shock and vibration of wheel-rail .The larger amplitude of harmonic local irregularity, the greater of the maximum wheel-rail vertical force. When deterioration of the amplitude exceeds a certain value, the maximum of the wheel-rail vertical force exceedes the limit, which will cause derailment. The wheel-rail dynamic interaction increases with the speed increasing. At the same speed (such as 120km/h), harmonic local irregularity settlement deterioration compareing to harmonic local irregularity raised deterioration, the maximum of the wheel-rail vertical force increases 14.4%. Therefore, local irregularity deterioration or the speed of the locomotive should be strictly controlled.