摘要 : The problem of high-speed water flow induced structural vibration during the flood discharge process of hydraulic structures has received increasing attention. This study reveals that the amplitude of the vibration response during... 展开 The problem of high-speed water flow induced structural vibration during the flood discharge process of hydraulic structures has received increasing attention. This study reveals that the amplitude of the vibration response during flood discharge in the vibration test of a prototype overflow dam pier at a hydropower station varies significantly over time, indicating the existence of impact-type beat vibration, which can easily induce strong vibration of the structure and even cause damage. A beat vibration analysis model for the overflow dam pier based on adaptive variational modal decomposition (VMD) and automatic operational modal analysis is proposed to further analyze the mechanism of beat vibration generation. First, a mathematical model of beat vibration is developed to investigate the production conditions of beat vibration. Secondly, based on adaptive VMD and automatic operational modal analysis method, the main working modal shapes, frequency ratio and amplitude ratio of dam piers are determined, and the main vibration components causing beat vibration are quantitatively extracted to analyze the internal cause of beat vibration. Finally, the external cause of beat vibration were analyzed from the perspective of hydrodynamic load characteristics by combining the hydraulic and hydroelastic physical model tests of the overflow dam pier. The results show that the proposed beat vibration analysis model can effectively explain the occurrence mechanism of beat vibration and determining and extracting the main vibration modal shapes that cause beat vibration, which can provide a theoretical basis for its structural vibration reduction. 收起