Dynamic investigation of carbody chattering induced by mode coupling resonance in high-speed train

High-speed train carbody chattering is a high-frequency abnormal vibration resulting from coupled resonance between the carbody diamond mode and hunting motion under low hunting stability conditions, leading to a significant degradation of ride comfort. This study examines the primary factors influencing the carbody chattering phenomenon, including carbody structure, wheel–rail matching conditions, and track elasticity. Initially, a vehicle–track coupled dynamics model is established to analyse carbody chattering dynamics. The mode coupling effect between the hunting mode and different carbody diamond modes is compared using the modal analysis method, providing a theoretical explanation for why carbody chattering predominantly occurs in specific cars. Subsequently, the effects of wheel–rail equivalent conicity functions and interface friction coefficients are examined in detail. Finally, the influence of track structural elasticity on carbody chattering behaviour is analysed. Results indicate that the shape of the carbody diamond mode and the frequency difference between the hunting frequency and the diamond modal frequency significantly affect carbody chattering characteristics. Moreover, a large nominal equivalent conicity with a negative slope induces a high hunting frequency, increasing the likelihood of carbody chattering. Track elasticity degrades hunting stability and shifts the coupled resonance velocity compared to idealised rigid tracks.