浮置板轨道参数激励振动研究

浮置板轨道结构中,浮置板布置的周期性和不连续性导致轨道刚度的周期性变化。车辆行驶在浮置板轨道上时,轨道刚度的周期性变化会引起参数激励振动。为了研究该问题,将钢轨和浮置板视为模态梁,钢轨扣件和隔振器视为线性弹簧-阻尼器;车辆采用相邻车厢距离最近的两台转向架模型,建立了车辆-浮置板轨道耦合动力学模型。应用该模型分析了浮置板轨道参数激励振动的形成机理及影响因素,提出了减小参数激励振动的控制措施。计算结果表明:振动的频率成分主要为车轮通过浮置板的频率及其倍频;轮轨作用力随着车辆速度的提高而增加,随着隔振固有频率的减小而增加;调整浮置板下隔振器的位置和刚度可以降低参数激励振动引起的轮轨作用力。

Parametric excitation vibration of a floating slab track

Although a floating slab track (FST) is an effective way to isolate the vibration transmitted to infrastruc-tures, the track's stiffness varies periodically in space due to periodic arrangement and discontinuity of floating slabs. This leads to a parametric excitation vibration when a train is moving over the track at certain speed. In order to make an inves-tigation into this issue, a vehicle-floating slab track coupling model was developed in the time domain and a solution based on the modal superposition method was proposed. Then, the parametric excitation vibration of FST and its affecting factorswere studied using this model. It was found that the main frequency components of such vibration were the floating slab passing frequency and its multiples; with the train speeding up or the natural frequency of the floating slab isolation system decreasing, the wheel/rail dynamic interaction force increased, and its peak-to-peak value was about 75 % of the static wheel/rail load when the vehicle run over the FST with natural frequency of 10 Hz or 6 Hz at a speed of 60 m/s; whereas,there existed a critical value of the single slab length, it corresponded to the larger wheel/rail dynamic interaction force as the single slab length changed; moreover, adjusting the installation location and the stiffness of the slab vibro - isolator could decrease the track variation; as a result, the wheeL/rail dynamic load from the parametric excitation vibration de-creased.