A Study On Dynamic Quality Of Railway Passenger Vehicle Based On Operational Modal Parameter Identification Technique

Ride qualities of some types of passenger vehicle and locomotives are deteriorated as a result of the speed-up of railway vehicles in China, some of which even cause the majority, especially those long journey passengers, feel sick and uncomfortable, though those vehicles are predicted very good running performances with their virtual prototypes. To cater for the rapid development of railway industry in China, a synthesized performance analysis with modal parameters (SPAMP) is proposed in this research, which depends not only on online test analysis and also on the theoretical analysis.For the first time, SPAMP technique applied on the locomotive and passenger vehicles is proposed by using both the theoretical modal parameter analysis and the operational modal parameter identification techniques. To improve the running performances of railway vehicle, this method connects the virtucal prototype with its real prototype by modal parameters, build relationships between the modal parameters and physical ones and the relationships between the modal parameters and the dynamic qualities through theoretical analysis, which can help judge the vehicle dynamic performances and help know how to improve them, and then use power spectral analysis, estimation of transfer functions and cohere functions to verify the identification and improvements made by SPAMP technique.After comparing the features, capabilities and precisions of several operational modal parameter techniques, taking consideration of the vibration and structure characteristic of railway passenger vehicles, the NExT (Natural Excitation Technique) and SSI (Stochastic Subspace Identification method) are applied to study the vibration quality under the operational contidion.Based on the MATLAB/Symbol development environment, the lateral and vertical symbolic equation of railway passenger vehicle are generated respectively using the matrix installation method, which is used to calculate the theoretical modal parameters after transferred into the state space equations.Measurement schemes on test rig are carefully designed according to the...