Abstract: The local resonance of the floor in high-speed EMU occurs frequently which generates a great negative impact on the comfort during vehicle operation. To explore the cause of formation mechanism and control measures of floor local resonance, a high-speed EMU vehicle combined with floor vibration measurement and simulation analysis is taken as the research object. The finite element model of the car body with refined components including aluminum honeycomb floor and floor elastic support is established, and the model is verified based on the vibration response and modal test results of the floor. Based on this model, it is found that the floor modal frequency is low due to the lack of local stiffness of the floor, and the excitation frequency transmitted to the car body through the bogie suspension is close to the floor modal frequency, which leads to the local resonance of the floor. Then two floor vibration control methods including local stiffness optimization and dynamic vibration absorption based on optimal acceleration response are proposed respectively, and the control effects are compared and analyzed. The results show that the proposed methods can both effectively restrain the local resonance of the floor, in which the local stiffness optimization method with corrugated plate can effectively improve the local stiffness of the floor and increase the modal frequency of the floor, avoiding the original excitation frequency, but it is easy to produce a new resonance frequency band. the dynamic vibration absorption method can realize the accurate control of the floor local resonance without the generation of additional resonance frequency band. In contrast, the dynamic vibration absorption floor vibration control method based on optimal acceleration response has a better performance in improving vehicle comfort.

Key words: high-speed EMU, floor vibration, structural optimization, dynamic vibration absorber