不同减振垫刚度下板式轨道减振特性研究

板式减振垫轨道能降低列车运营对周围环境的影响,确保城市轨道交通引起的振动满足环保要求,在高等减振设计中普遍采用。基于轮轨耦合作用,建立城轨列车-板式减振垫轨道-下部基础有限元模型,对不同减振垫刚度下板式轨道结构进行模态、谐振分析,并对其减振性能进行研究。研究表明:(1)减振垫轨道结构的固有频率随着减振垫刚度的增大而增大,振型包括轨道板的平动、转动、弯曲和钢轨的侧翻、扭转;(2)钢轨至轨道板的传递损失集中在15~30 d B,而轨道板至基底的传递损失峰值达51 d B;(3)车体加速度、轮轨垂向力、钢轨加速度、基底垂向加速度随着减振垫刚度的增大呈增大趋势,而钢轨位移、轨道板加速度和位移呈减小趋势;(4)板式减振垫轨道在25~100 Hz频段的减振效果较好,特别是1/3倍频程中心频率63 Hz处,插入损失达24 d B;在1~25 Hz频段的减振效果一般,而且局部频段出现振动放大的情况。

Study on Vibration Reduction Characteristic of Slab Track with Different Rubber Absorber Stiffness

Slab track with rubber absorber is widely used to reduce the influence of train operation on the surrounding environment,which ensures the compliance of the vibration with specification requirements.Based on wheel-track coupling dynamics,an urban train-slab track with rubber absorber-infrastructure model is established to analyze the modal and resonance of the slab track with rubber absorbers of different stiffness,and the vibration reduction performance is also studied. Research results show that:(1) the natural frequency of the slab track with rubber absorber increases with the increase of stiffness,and the vibration mode includes translation,rotation and bending of the track slab as well as rollover and twist of the rail;(2) the transmission loss from rail to track ranges from 15 d B to 30 d B with the peak up to 51 d B from track to foundation;(3) car-body acceleration,wheel-rail vertical force,rail acceleration and foundation acceleration increase with the increase of the rubber absorber stiffness,while,the rail displacement,track slab acceleration and displacement tend to decrease;(4) the slab track with rubber absorber tends to have better damping effect at 25 ~ 100 Hz frequency,especially at 1/3 octave band center frequency of 63 Hz,the insertion loss is up to 24 d B; and the effect at 1 ~ 25 Hz is general and vibration amplification appears in some frequency bands.