某三跨斜拉桥纵向设置液体黏滞阻尼器阻尼系数优化

以某跨海大桥为例，采用有限元软件MIDAS建立三维空间有限元模型，考虑桩-土效应，研究在地震荷载作用下，阻尼器的阻尼比与阻尼指数之间的关系。根据能量等效原理，推导出非 线性阻尼器最优阻尼系数，提出一种阻尼器参数优化的新方法。研究发现：当桥梁设置线性黏滞阻尼器时，体系的最优阻尼比近似等于0.5，与不设置黏滞阻尼器且阻尼比为0.05 时的耗能能力近似相等；当阻尼器为非线性时，随着阻尼指数的增大，最优阻尼系数逐渐减小，结构位移逐渐增大；非线性阻尼器的减震效果优于线性阻尼器。这种阻尼器参数优化的新方法不仅可以大大减少计算时间，而且可以直接得到最优阻尼系数和最优阻尼比。

Damping Coefficient Optimization of Longitudinal Fluid Viscous Damper for a Three-Tower Cable-Stayed Bridge

Taking a sea bridge as an example, the three-dimensional space finite element model considering the pile-soil interaction of the bridge was established by MIDAS, to research the relation between damping ratio and damping index under the action of earthquake load. The optimal damping coefficient of nonlinear fluid viscous damper was deduced based on the principle of energy equivalent, and a new method of damper parameters optimization was proposed. The results show that: when the linear viscous damper was set in bridge, the optimal damping ratio of the system was 0.5 approximately, which was approximately equal to the energy dissipation capacity of the system with no fluid viscous damper meanwhile the damping ratio was 0.05; for the nonlinear fluid viscous damper, the optimal damping coefficient decreased with the increase of damping index, the structural displacement also gradually increased; the damping effect of nonlinear dampers was better than that of linear dampers. It indicates that the new method of damping coefficient optimization can greatly reduce the computation time, and can directly obtain the optimal damping coefficient and the optimal damping ratio.