高速铁路连续箱型梁桥的动力响应与减振分析

根据列车具体的轴距和轴重,建立了和谐号动车组CRH380AL型列车简化模型;对高速铁路两跨连续梁桥采用多自由度欧拉伯努利梁单元进行主梁的模拟,并将液体黏滞阻尼器模拟为有限元阻尼单元;采用Newmark直接积分方法求解了高速列车作用下的连续梁桥运动方程,数值分析了列车车速以及液体黏滞阻尼器的阻尼系数对于高速铁路连续梁桥振动响应的影响。结果表明:黏滞阻尼器对于桥梁具有明显的减振效果,阻尼力不仅与阻尼系数有关还与列车时速有关;同一黏滞阻尼器条件下,桥梁的最大加速度并不随列车速度的增加而单调增加,而是在某些特定列车车速下桥梁的最大加速度出现了峰值,且随着黏滞阻尼器的阻尼系数增大,桥梁振动响应峰值处的最大加速度减幅不同;同一列车时速的条件下,桥梁的减振效果并不是随着阻尼系数的递增呈正比递增,而是随着阻尼系数的增大,阻尼器的减振效果增幅在减小。

Dynamic response and vibration reduction analysis of high-speed railway continuous box girder bridge

As the speed of high-speed trains in China increases,the coupled vibration between vehicle and bridge becomes more and more severe,and the dynamic response and vibration reduction analysis of the coupled system become more and more important.In this paper,a simplified model of CRH380AL train is established based on the specific wheelbase and axle weight of the train firstly.Then,for the existing two-span continuous girder bridge with high-speed railway,the main girder is modeled with the Euler Bernoulli beam element with multiple degrees of freedom,and the viscous dampers are modeled as finite element damping elements.Finally,the Newmark direct integration method is used to solve the motion equation of the continuous beam bridge under the action of high speed train,and the influences of train speed and damping coefficient of liquid viscous damper on the vibration response of high-speed railway continuous beam bridge are numerically analyzed.The numerical results show that:the viscous dampers have obvious damping effect on the bridge,which relates not only to the damping coefficients but also to the speeds of the train;in the same condition of viscous dampers,the maximum acceleration of the bridge does not increase monotonously with the increase of train speed,but the maximum acceleration of the bridge under certain train speeds appears a peak,and with the damping coefficients of viscous damper sincrease,the maximum acceleration at the peak of the vibration response of the bridge decreases with different amplitudes;the vibration reduction effect of the bridge is not proportional to the increase of the damping coefficients under the same train speeds,but with the increase of the damping coefficients,the increase amplitudes of the vibration reduction effect of the dampers is decreasing.