钢轨扣件弹性垫板的宽频动力性能及其理论表征

Broad Frequency-domain Dynamic Properties of Rail Pad and Its Theoretical Model

以我国高速铁路无砟轨道Vossloh300扣件弹性垫板为研究对象,针对轮轨宽频激励特点,利用万能试验机和温度箱,测试定频(0.3Hz)低温(-60～20℃)条件下弹性垫板在不同平衡预压与不同动载振幅组合下的动力性能;应用温频等效原理、WLF方程与分数阶Zener模型,预测与表征弹性垫板的宽频动力性能。研究结果表明:Vossloh300扣件弹性垫板的储能刚度与损耗因子随着平衡预压的增加而增大;20℃时,分数阶Zener模型可有效表征Vossloh300扣件弹性垫板在1～10 000Hz范围内的储能刚度与损耗因子,温度较低时,建议使用五参数模型;从更宽频域的分数阶Zener模型结果来看,随着平衡预压的增加,Vossloh300扣件弹性垫板损耗因子的频域峰值将升高,其峰值宽度也将变窄。

Based on the study of the elastic pads in Vossloh 300 rail fasteners used in the non-ballasted track of Chinese high-speed railway,according to the broad frequency-band features of wheel-rail excitation,the dynamic mechanical characteristics of the test rail pad caused by the different preloads or the different dynamic loads at the constant frequency of 0.3 Hz were measured by the universal testing machine equipped with temperature control box in the temperature range of -60~20 ℃.Then,the time-temperature superposition,WLF formula and fractional derivative Zener model were applied to predict and represent the broad frequency-domain dynamic properties of the test rail pad.The research results show that the energy storage stiffness and loss factor of Vossloh 300 rail pad would increase with the increase of balanced preload.Although fractional derivative Zener model can effectively represent the energy storage stiffness and loss factor of Vossloh 300 rail pad in the range of 1~10 000 Hz at 20 ℃,five-parameter fractional derivative model is suggested for representation when the temperature drops a lot.Observed from the results calculated by fractional derivative Zener model in broader frequency-band,with the increase of balanced preload,the peak value in the frequency domain of the loss factor of Vossloh 300 rail pad will increase and its peak width will get narrower.