The Vehicle Dynamics Analysis Based On Amesim Model Of Air Spring

With the railway traffic’s speed increasing and the development of the motor car, the air spring has been widely used in many areas such as railway vehicles, EMU, subway, light rail, maglev train and so on, and gradually replace the traditional secondary suspension systems. In the conventional vehicle dynamics analysis, the air spring is simplified as a linear spring and damping in parallel system. The air spring is a complex system actually. It is composed by airbags, additional air chamber, orifice, the height control valve, the differential valve and so on. Conventional air spring model can’t reflect the real role of air spring in the vehicle, it makes the dynamic performance of vehicle with air spring system in the large error, it not conducive to vehicle parameters optimization. In order to solve the above problem, a new air spring model is established, and its validation is analysed.CRH380A vehicle dynamics model and air spring model are established by using multi-body dynamics software SIMPACK and AMESim software. According to the action principle of air spring, the CRH380A model and the air spring model are conneted, thus can achieve data transmission. The vehicle dynamics performance is analysed according to the GB5599-85, and compared with the vehicle dynamics performance which is calculated by conventional air spring model. The analysis results show that the vehicle dynamic performancein dexes based on AMESim air spring meet the evaluation criteria, the vehicle dynamic performance index error is smaller under the two models of air spring.The gas dynamics equations of rubber balloon, additional air chamber and orifice gas is built based on the theory of thermodynamics and fluid mechanics. The impact on straight smooth running of the vehicle is analyzed which is caused by the volume of additional air chamber and orifice diameter. The impact on the dynamic performance of the vehicle is analyzed which is caused by the none sense zone of height control valve and parameter of delay time and differential pressure value of differential pressure valve, and the impact on the safe operation of the vehicle is also analyzed which is caused by differential pressure valve under the circumstances that the air spring has broken.In the model of air spring based on AMESim software, complicated changes and process of air spring can be reflected, the flow of height control valve and differential pressure valve, the pressure of airbag and additional air chamber can be observed, the effect to the performance of vehicle dynamics which caused by a variety of air spring system parameters can be analyzed, the break of air spring can be simulated. The dynamic performance dexes of the vehicle are more true and reliable compared with the conventional model.