Effect Of Out-Of-Round Wheel On Vehicle System Dynamics Behavior

Out-of-roundness (OOR) arises on wheel treads of some high-speed trains from the opening of high-speed railway in China, which could lead to abnormal structural vibration and negatively affect the riding comfort and the trains’operation safety. In order to understand the wheel OOR development law and its effect on vibration characteristics of vehicle system’s key components, wheel wear and vibration of key components are measured in tracking tests of high-speed vehicles in this thesis. Then based on the field test, the influence of wheel OOR on high-speed vehicle dynamic behavior is investigated by using theoretical modeling. The main work and the conclusions are as follows:1. Based on the vehicle system dynamics theory, a three-dimensional rigid-flexible coupling high-speed vehicle system dynamics model is established. The model considers the carbody flexibility, including the carbody’s central diamond, breathing mode, vertical bending, lateral bending and the torsional mode. The flexible carbody modes are validated, and the responses of the vehicles running on tangent and curve tracks by using the multi-rigid-body model and the rigid-flexible coupling model are compared.2. Wheel wear and vibration of key components of three types of high-speed vehicle of China are measured under different running mileage in different wheel re-profiling cycles. The wheel OOR characteristics and development law are analyzed. The relationship between the wheel OOR and the characteristics of key components’vibration is investigated.3. It is from the measure found that the wheels in the first re-profiling cycle mainly show trilateral shape wear characteristics, while periodic OOR with twenty periods around the wheel circumference arises in the second cycle. Polygonal wear shape of wheel can aggravate the vibrations of axle-box, bogie-frame and carbody-floor. Wheel re-profile can effectively reduce the radius deviation and the vibration. But if the wheels circumferential non-uniform material hardening cannot be effectively eliminated, it will accelerate the development of wheel OOR.4. Based on the measure results of wheel OOR, the influence of wheel OOR on the high-speed vehicle system dynamic behavior is analyzed by using the above established three-dimensional rigid-flexible coupling high-speed vehicle system dynamics model. The numerical results show that an increase of wheel radial runout leads to fierce wheel-rail dynamic behavior, and some wheel OOR orders result in the resonance of vehicle system components and then increase the system vibration.