Research on multi-point connection of under-chassis equipment suspension system in high-speed trains

A power dispersive high-speed electric multiple-unit (EMU) train requires the installation of traction equipment under the carbody. As the speed of high-speed trains increases, the demand for traction power is increasing, and the weight and size of the equipment have increased accordingly. To adapt to the research and development of higher-speed EMU trains, this research proposes the use of a multi-point connection scheme for installing the under-chassis equipment. First, the static deflection and supporting reaction force of each hanging point are obtained based on static analysis, and it is found that increasing the number of connection points is beneficial for reducing the static stiffness requirement of each rubber element. Then, an energy decoupling degree is introduced, and an optimization design method for the hanging point stiffness is proposed based on the energy decoupling degree and optimal vertical suspension frequency. Finally, a rigid-flexible coupling dynamics simulation model is established to analyze the vibration characteristics of the carbody and equipment after decoupling and optimization of the multi-point suspension schemes. The research results show that after the decoupling optimization, the vibration amplitude in the middle of the carbody is effectively reduced, and the ride quality of the carbody is improved. The difference in the number of hanging points has little effect on the vibration performance of the carbody, but increasing the number of hanging points is beneficial for reducing the dynamic supporting reaction forces of the hanging components, thereby reducing the dynamic stress of the rubber elements.