铁道建筑

以我国城市轨道交通扣件中常用的单趾弹条为研究对象，基于多参考点锤击测试技术，对其在组装状态下的模态特征进行了试验研究。结果表明：组装状态下，单趾弹条在0～1 000 Hz频率范围内存在3阶模态振型，对应的固有频率平均值分别为485、593、707 Hz；第1阶振型为以跟端和趾端为支撑点，大圆弧和小圆弧反向振动；第2阶模态振型为以趾端、小圆弧到弹条中肢的相切点为支撑点，弹条中肢和大圆弧同向振动；第3阶模态振型为以跟端、趾端和弹条中肢为支撑点，大圆弧和小圆弧反向振动；弹条中肢插入长度在72～78 mm内变化时，其固有频率无明显变化。建议通过提高单趾弹条的固有频率、改变列车运行速度等方法，避免轮轨激励频率与弹条固有频率一致，延长弹条的使用寿命。

Taking the commonly used PR clip in urban rail transit fasteners in China as the research object, based on multi reference points hammering test technology, the modal characteristics of it in the assembled state were experimentally studied. The results show that in the assembled state, the PR clip has 3rd mode shapes in the frequency range of 0 ～ 1 000 Hz, with corresponding average natural frequencies of 485, 593 and 707 Hz. The 1st mode shapes are supported by the heel and toe ends, with large and small arcs vibrating in opposite directions. The 2nd mode of vibration is supported by the tangent point between the toe end and the small arc to the middle limb of the elastic bar, and the middle limb of the elastic bar vibrates in the same direction as the large arc. The 3rd mode vibration is supported by the heel end, toe end, and middle limb of the elastic bar, with large and small arcs vibrating in opposite directions. When the insertion length of the limb of the PR clip varies within 72 ～ 78 mm, there is no significant change in its natural frequency. It is recommended to increase the natural frequency of the PR clip and change the train operating speed to avoid the wheel-rail excitation frequency being consistent with the natural frequency of the PR clip, and to extend the service life of the PR clip.