钢弹簧浮置板中低频振动特性分析

摘要

为了探究高架线路上钢弹簧浮置板减振轨道在外激励作用下的振动特性,建立钢弹簧浮置板减振轨道-箱梁桥三维有限元模型,以美国六级谱激励下的轮轨力作为输入,对钢弹簧浮置板减振轨道的振动特性进行系统的研究;在此基础上,分析不同刚度的钢弹簧对整体轨道结构振动的影响.研究结果表明:浮置板结构的振动特性以纵向上的弯曲振动为主,同时存在不均匀分布的局部振动特性,因此只有利用三维有限元模型才能很好地研究浮置板结构的整体和局部振动特性.整体轨道结构在中低频段的振动明显,其中钢轨的主振频率集中在200 Hz～250 Hz 以及425 Hz～475 Hz;浮置板在150 Hz以下的低频段振动密集,主振频段与钢轨一致,但在425 Hz～475 Hz的振动幅值与低频段相近;浮置板在主振频段的弯曲振动不是规则的同幅值正弦形式,其幅值呈逐渐递增或递减分布.钢弹簧刚度对钢轨50 Hz以下的振动频率分布有一定的影响;主要影响浮置板结构的整体振动形式,在频率较低时对振动幅值及局部振动形式也有较大的影响.%In order to explore the vibration characteristics of damping rails of steel spring floating slabs on elevated tracks under external excitation, the three-dimensional finite element model of the box girder bridge with the steel spring floating slab damped rails on is established. With the wheel force under American sixth level spectrum excitation as the input, the vibration characteristics of steel spring floating slab damping rails are systematically studied. On this basis, the influence of steel spring with different stiffness on the whole track structure vibration is analyzed. The research results show that the vibration characteristics of the floating plate structure are mainly the longitudinal bending vibration. At the same time there is an uneven distribution of local vibration characteristics. Therefore, it is only the three-dimensional finite element model, which can study the global and local vibration characteristics of the floating slab structure. The overall track structure has obvious vibration in low and middle frequency ranges. The main vibration frequency of the rail is focused on the 200 Hz - 250 Hz and 250 Hz - 475 Hz ranges. The vibration amplitude of the floating plate in the low frequency band below 150 Hz is the same as that of the rail, but the vibration amplitude in 425 Hz - 475 Hz range is close to that in the low frequency band. Floating slab in the main vibration frequency of bending vibration is not the pure sinusoidal form with the same amplitude. Steel spring stiffness has some influence on the vibration of the rail below 50 Hz frequency. It mainly affects the overall vibration mode of the floating slab structure, and also has a great influence on the vibration amplitude and local vibration form in lower frequency range.