既有高速铁路提速条件下低频晃车特征及影响因素研究

Study on characteristics of low frequency car body swing of existing high-speed railway with speed increase and its influence factors

针对某高速铁路列车在运营速度由200 km/h提升至250 km/h后,部分直线区段出现的车体横向低频晃动现象开展试验研究和仿真分析。首先对比分析提速前、后轨道动态检测数据在晃车区段和未晃车区段的时频特征以及乘坐舒适性,进而研究晃车区段的轮轨接触特性,通过建立车辆-有砟轨道动力相互作用模型,深入分析轮轨廓形、列车运行速度以及轨道平顺状态对高速铁路直线运行晃车问题的影响。研究结果表明:当列车提速至250 km/h后,晃车区段车体横向加速度出现明显周期性波动,振动频率为1.37 Hz,与提速前相比,车体横向加速度振动幅值增加了一倍,舒适性等级接近超限,乘坐舒适性明显降低;与采用CHN60&LMA廓形相比,采用实测轮轨廓形时的轮对蛇形运动加剧,轮对运动向一侧钢轨偏移,直接影响车体横向振动频率;列车运行速度提高后车辆系统响应对轮轨廓形的变化更为敏感,采用实测轮轨廓形,列车运行速度为250 km/h时的车体横向加速度谱峰较运行速度为200 km/h时的增大了1.6倍,较采用CHN60&LMA廓形时的增大了1.5倍;当列车提速至250 km/h后,轨道不平顺振动频率与轮对蛇形运动频率相同,轮轨动态响应进一步加剧,从而造成车体产生横向低频晃动。

Experimental research and simulation analysis were carried out for the phenomenon of transverse lowfrequency swing of car body when the running speed of a high-speed railway was increased from 200 km/h to 250 km/h.The time-frequency characteristics and ride comfort of track dynamic measuring data of swing and nonswing sections were compared and analyzed,and the wheel-rail contact characteristics of swing section were studied.Then,through the establishment of vehicle-ballasted track dynamic interaction model,the influences of the wheel-rail profiles,train speed and track irregularity on the problem of car body swing were studied.The results show that after the train speed is increased to 250 km/h,the transverse acceleration of the car body on the swing section fluctuates obviously periodically,and the vibration frequency is 1.37 Hz.Compared with that before the speed increase,the vibration amplitude of the transverse acceleration of the car body is doubled,the comfort level is close to exceeding the limit,and the riding comfort is obviously deteriorated.Compared with CHN60LMA profile,the wheelset hunting motion is intensified when the measured wheel-rail profile is adopted,the wheelset motion deviates to the left rail,and changes with the transverse vibration frequency of the car body.After the train speed is increased,the response of vehicle system is more sensitive to the change of wheel-rail profile.Using the measured wheel-rail profile,the spectral peak of lateral acceleration of car body at the running speed of 250 km/h is 1.6 times higher than that at the running speed of 200 km/h,and 1.5 times higher than that when CHN60LMA profile is adopted.After the train speed is increased to 250 km/h,when the track irregularity vibration frequency is equal to the wheelset hunting motion frequency,the wheel-rail dynamic response will be intensified,resulting in lateral low-frequency swing of the car body.