Study on multi-degree of freedom dynamic vibration absorber of the car body of high-speed trains

Abstract. To absorb the vibration of the car body of the high-speed train in multiple degrees of freedom, a multi-degree of freedom dynamic vibration absorber (MDOF DVA) is proposed. Installed under the car body, the natural frequency of the MDOF DVA from each DOF can be designed as a DVA for every single degree of freedom of the car body. Hence, a 12-DOF model including the main vibration system and an MDOF DVA is established, and the principle of Multi-DOF dynamic vibration absorption is analyzed by combining the design method of a single DVA and genetic algorithm. Based on a high-speed train dynamics model including an under-car-body MDOF DVA, the vibration control effect on each DOF of the MDOF DVA is analyzed by the virtual excitation method. Moreover, a high static and low dynamic stiffness (HSLDS) mount is proposed based on a cam–roller–spring mechanism for the installation of the MDOF DVA due to the requirement of the low vertical dynamic stiffness. From the dynamic simulation of a non-linear model in the time domain, the vibration control performance of the MDOF DVA installed with a nonlinear HSLDS mount on the car body is analyzed. The results show that the MDOF DVA can absorb the vibration of the car body in multiple degrees of freedom effectively and improve the running ride quality of the vehicle.