浮置板轨道减振垫的刚度测试与评价

Stiffness Test and Evaluation Method of Floating Slab Track Damping Pad

为了科学测试与评价浮置板轨道减振垫刚度,为浮置板轨道静动力学特性分析提供准确的计算参数,通过有限元仿真计算减振垫测试样品的荷载施加范围,应用配备温度箱的力学试验机并结合温频等效原理测试了减振垫静刚度以及5.0、10.0、20.0、30.0 Hz频率下的动刚度;在得到减振垫准确力学参数的基础上,对比分析了采用传统4.0 Hz参数与真实频变参数对浮置板轨道固有频率以及导纳特性的影响.研究结果表明:浮置板轨道变形、静力学分析以及底座板弯曲变形应分别采用3种不同荷载范围下的静刚度;浮置板轨道调谐频率,安全性以及减振效果应分别采用3种不同预压条件下的动刚度;无(有)车载条件下聚氨酯减振垫4.0 Hz参数得到的浮置板固有频率为27.0 Hz(15.5 Hz),而考虑频变刚度的真实固有频率为31.5 Hz(18.3 Hz);采用4.0 Hz减振垫参数分析浮置板振动传递特性将会低估浮置板轨道固有频率,高估隔振频带及隔振效果;当采用浮置板轨道真实一阶固有频率对应的减振垫参数,其导纳计算结果与考虑减振垫真实频变特性基本一致.

The purpose of this study was to test and evaluate the stiffness of the damping pad of a floating slab track and to provide accurate calculation parameters for the dynamic simulation analysis of the floating track.In this study,the load application range of the damping pad test samples was calculated in a finite element simulation,and the static stiffness and dynamic stiffness(5.0、10.0、20.0、30.0 Hz)of the damping pad were tested and evaluated using a mechanical testing machine equipped with a temperature control box and combined with time-temperature superposition.On the basis of the actual mechanical characteristics of the anti-vibration damping pads,the effects of using traditional 4.0 Hz parameters and actual frequency-dependent parameters on the simulated natural frequency and admittance characteristics of the floating slab track were compared and analyzed.The results show that the static stiffness of damping pads should be tested in three different load ranges according to the deformation,static analysis and analysis of the bending deformation of the base plate.The dynamic stiffness of damping pads should be tested under three different preloading conditions according to the tuning frequency,safety and insertion loss analysis of the floating slab track.In the case of no vehicle load(under a vehicle load),the natural frequency of the floating slab obtained using the 4.0 Hz parameters of the polyurethane damping pad is 27.0 Hz(15.5 Hz),whereas the true natural frequency after considering the frequency-dependent stiffness of the damping pad is 31.5 Hz(18.3 Hz).The natural frequency of the floating slab track would be underestimated and the vibration isolation frequency band and vibration isolation effect would be overestimated if parameters obtained at 4.0 Hz are used to analyze the vibration transfer characteristics of the floating slab track.The admittance results obtained with the parameters at the first-order frequency of the floating slab track are basically consistent with those obtained using the actual frequency-dependent characteristics.