钢轨轧制不平顺激扰下的动车组动力响应特性

以某有砟客运专线中出现波长为3.2 m的轨道周期性高低不平顺、继而引起“抖车”现象的线路区段为对象，基于同步压缩小波变换提取了轨道几何动、静态检测数据在大机捣固前后的时频分布特征，并结合钢轨轧制流程的梳理分析，明确了轨道周期性高低不平顺的成因，即可能由钢轨轧制过程中复合矫直工艺不良引起. 在此基础上，探究了钢轨轧制不平顺与车辆各部件振动加速度以及轮轨接触力的关联关系，获取了钢轨轧制不平顺对车辆动力响应的影响规律. 结果表明:轧制不平顺使得轴箱、转向架、车体垂向加速度的相干函数分别达到0.97、0.96和0.76，较正常区段分别增长了5%、25%和300%；轮轨垂向力相干函数增长42%，达到0.94，说明轧制不平顺与车辆各部件的振动响应和轮轨接触力密切相关；轧制不平顺将轴箱和车体垂向加速度均方根（root mean square，RMS）值分别放大1.00 m/s2和0.05 m/s2左右；轧制不平顺与轴箱垂向加速度和轮轨垂向力RMS值线性相关性最强，相关系数分别达到0.9和0.8. 

Dynamic Response Characteristics of EMU under Excitation of Rail Straightening Irregularity

A section on a ballasted passenger dedicated line is targeted, where the periodic longitudinal unevenness occurs with the wavelength of 3.2 m, leading to vehicle shaking. Based on the synchrosqueezed wavelet transform, the time-frequency distribution of the dynamic and static track geometry detection data before and after machine tamping is extracted. Combined with the analysis on rail straightening process, the causes of periodic longitudinal unevenness are clarified, which may be caused by poor composite straightening process in rail rolling. On this basis, the relationship between rail straightening irregularity, vibration acceleration of vehicle components, and wheel rail contact force are explored, and the influence of rail straightening irregularity on vehicle dynamic performance is obtained. The results show that the coherence functions of vertical accelerations at axle box, bogie and car body are 0.97, 0.96 and 0.76 respectively, which increase 5%, 25% and 300% respectively than that on the normal section. The coherence function of wheel rail vertical force is increased by 42% to 0.94, revealing that straightening irregularity is closely related to the vibration response of vehicle components and wheel-rail contact force. Due to straightening irregularity, the RMS value of vertical acceleration at axle box and car body are amplified by about 1.00 m/s2 and 0.05 m/s2 respectively. Straightening irregularity has a strongest linear correlation with the RMS values of vertical accelerations at axle box and wheel-rail vertical force with the correlation coefficients of 0.9 and 0.8 respectively.