基于振幅放大机制的周期钢弹簧浮置板轨道结构低频振动控制

Low Frequency Vibration Control of Periodic Steel Spring Floating Slab Track Based on Amplitude Amplification Mechanism

钢弹簧浮置板轨道结构因其具有良好的减隔振性能在城市轨道交通中应用广泛,但对于20 Hz以下的低频振动,尤其是人体敏感频率范围内(4~8 Hz)的隔振效果并不理想。鉴于此,引入振幅放大思想,设计了一种杠杆式隔振器,用于有效提升钢弹簧浮置板轨道在人体敏感频率范围内的隔振效果。基于钢弹簧浮置板轨道结构的周期性特征,采用能量泛函变分法并结合人工弹簧技术建立了配置有杠杆式隔振器的周期性钢弹簧浮置板轨道结构带隙特性分析模型;以带隙特性作为评价指标,从研究振动波传递的角度出发,系统地分析了配置有杠杆式隔振器的钢弹簧浮置板轨道结构中弯曲振动波的传递路径特征,验证了杠杆式隔振器对轨道结构中低频弯曲振动波的调控作用。在此基础上,进一步考虑列车荷载的作用,分析验证了动态轮轨力作用下杠杆式隔振器的低频隔振性能以及对轨道结构动力响应的影响。结果表明:杠杆式隔振器对浮置板轨道的低频弯曲波调控效果明显,由0~9.6 Hz成功调控至4 Hz以下;与普通浮置板轨道相比,4~8 Hz范围内传递至下部基础的力大幅度衰减,最大衰减约20 dB,同时,杠杆式隔振器对轨道结构的振动也有一定的抑制效果。

Steel spring floating slab track structures are widely used in urban rail transport due to their excellent vibration damping performance.However,the vibration isolation effect could be better for low frequency vibrations below 20 Hz,especially in the human body-sensitive frequency range(4 to 8 Hz).Given this,a lever-type vibration isolator has been designed to effectively improve the vibration isolation of steel spring floating slab tracks in the human-sensitive frequency range by introducing the idea of amplitude amplification.Based on the periodic characteristics of steel spring floating slab track structures,an analytical model of the band gap characteristics of periodic steel spring floating slab track structures equipped with lever-type vibration isolators is developed using the energy-generalized variational method combined with artificial spring technology.The transmission path characteristics of flexural vibration waves in steel spring floating slab track structures equipped with lever-type vibration isolators are systematically analyzed from the perspective of vibration wave transmission by using the band gap characteristics as an evaluation index.Regulation of low frequency flexural vibration waves in track structures by lever-type vibration isolators is verified.On this basis,the low frequency vibration isolation performance of lever-type vibration isolators under dynamic wheel-rail forces and the effect on the dynamic response of the track structure are analyzed and verified.The results indicate that:the lever-type vibration isolator has obvious control effect on the low-frequency flexural wave of the floating slab track,which is successfully regulated from 0~9.6 Hz to below 4 Hz.Compared with the ordinary floating slab track,the force transmitted to the lower foundation in the range of 4~8 Hz is greatly attenuated,and the maximum attenuation is about 20 dB.At the same time,the lever vibration isolator also has a certain suppression effect on the vibration of the track structure.