三维离散支承浮置板轨道动力响应频域模型研究

Dynamic response analysis model of a 3D floating slab track with discrete supports in frequency domain

基于欧拉梁理论、Kirchhoff薄板理论和无限周期结构理论,建立三维离散支承浮置板轨道动力响应频域模型。钢轨和浮置板的位移均通过模态叠加法进行表示,其中浮置板振型函数由双向梁振型函数组合得到。利用移动谐振荷载作用下无限周期结构理论及振型函数正交等性质,通过求解轨道在一个周期内的动力响应,进而得到无限长轨道上任一点的动力响应。该研究对二维、三维模型的计算结果进行对比,并对左右钢轨作用激振频率不同的单位移动谐振荷载时浮置板轨道的动力响应进行研究。结果表明:移动谐振荷载作用于左侧钢轨时,由于浮置板和钢轨的耦合作用,会同时激发右侧钢轨的振动,且右轨振动响应的频域特征与浮置板振动响应特征较为相似;当两钢轨上荷载的激振频率不同时,较低激振频率的荷载作用侧的轨道振动响应更为强烈。

A floating slab track model was established in frequency domain,which was based on the Euler-beam theory,Kirchhoff theory and the theory of periodic-infinite structure.The displacements of the rails and slabs were expressed by mode superposition method.According to the characteristics of periodic structures and the orthogonality of the mode functions,the dynamic response of the track at any position could be obtained by calculating the response at the corresponding point in the range of one slab when harmonic loads moving along the rails.The track dynamic responses calculated by the 2D and the 3D model were compared.By using the model,the track displacement responses were obtained when the excitation frequencies of moving harmonic loads on both rails are different.The results show that:when a unit harmonic load moves along the left rail,the right rail also vibrates because of the effect of the slab,and the dynamic performance of the right rail is much similar to the performance of the slab.When the frequencies of the loads moving along the two rails are different,the dynamic response on the track side subjected to the load with lower frequency is much higher than that on the other side.