Critical State Evaluation Method for Dynamic Derailment of High Speed Vehicle

In view of the limitation of the traditional quasi-static derailment coefficient index in monitoring the dynamic derailment safety of high-speed vehicles, this paper proposes a judgment criterion for derailment critical state based on the wheel vertical rise and the wheelset lateral displacement, which is determined by the wheelset motion gesture. A multi-body dynamic model of high-speed vehicle is established to analyze the nonlinear dynamic characteristics of high-speed vehicle dynamic derailment. The relationship between wheelset motion gesture and vehicle dynamic response is investigated, and the results show that the wheelset lateral acceleration is in good agreement with the wheel vertical rise. When using the proposed dynamic evaluation criteria for the dynamic derailment of high-speed vehicles, the root mean square value of the wheelset lateral acceleration is first used as an index to evaluate the derailment of vehicles. Then the filter frequency range and filter time window width when the index can effectively reflect the change of wheel vertical rise should be determined. Finally, the reasonable limit value of the index is determined. Numerical simulation results show that the evaluation criteria can effectively monitor the dynamic derailment safety. The statistical waveform of the root mean square value of the wheelset lateral acceleration almost has the same trend with the wheel vertical rise. The new index can not only indirectly reflect the change of wheelset motion gesture and the wheel vertical rise, but also overcome the defect of the derailment coefficient distortion when the wheel-rail vertical force is zero, thus it is more reliable in evaluating the high-frequency dynamic derailment. © 2020, Editorial Department of China Railway Science. All right reserved.