Evaluation Methods of Carbody Hunting Instability of Railway Vehicles

In order to analyze and make the criterion of carbody primary hunting instability, the relationship among equivalent conicity, vehicle speed and hunting frequency has been analyzed firstly. To simulate different vehicles' carbody hunting instability, this article analyzed the lateral acceleration signals of a simulated full-scale vehicle under several conditions. Through these data, an amendatory method for calculating centroid frequency of vehicle lateral vibration is presented and an index named power concentration ratio (PCR) is presented for distinguishing carbody primary hunting and the data with larger amplitude is screened under the ride index. According to the statistical law, the criterion of carbody primary hunting instability is summarized. Research result shows that the there is a vehicle carbody hunting instability while the lateral acceleration with filtered 0.5-3 Hz exceeds 0.5 m/s(2) for six times serially in 15 s. The criterion is shown to be valid through the field test data.