Objective When high-speed EMUs (electric multiple units) operate at speeds exceeding 300 km/h, vehicle end abnormal vibrations may occasionally occur, leading to increased interior noise and resonance phenomena. To effectively improve the reliability of high-speed EMU components and enhance ride comfort, it is necessary to investigate the vehicle end abnormal vibration.

Method Based on the characteristics of high-speed EMU vehicle end structure, an analysis is carried out on the causes of vehicle end abnormal vibrations from two aspects: the aerodynamic excitation characteristics of the windshield area and the modal characteristics of the end wall, thus the vibration frequencies inside the windshield cavity and the natural modal frequencies of the end wall are obtained. Based on the internal and external factors influencing vehicle end vibration, both active and passive optimization schemes are proposed. The feasibility of the proposed vibration reduction and noise control technologies is verified through simulation analysis and actual line tests.

Result & Conclusion  Since the aerodynamic excitation frequency of the windshield is close to the natural modal frequency of the end wall, it can easily induce local resonance of the end wall and result in the vehicle end abnormal vibration. Based on the mechanism of abnormal vibration generation, vibration reduction and noise control can be achieved by measures such as increasing the modal frequency of the end wall structure, installing particle dampers, and optimizing the windshield structure.