阻尼器支架刚度对悬索桥吊索减振效果影响的数值研究

采用数值方法,研究了阻尼器支架刚度对悬索桥吊索减振效果的影响.首先,将阻尼器支架简化为弹簧振子模型,建立了吊索-阻尼器-支架系统的自由振动偏微分方程组.其次,对不连续的狄拉克函数进行近似处理,采用有限差分方法对该方程进行数值离散求解,研究了阻尼器支架刚度对无量纲阻尼比曲线、可实现的最优阻尼比及其对应的最优阻尼系数等的影响,研究了阻尼器支架模态质量的影响,并与相关文献结果进行比较.研究结果表明,随着阻尼器支架刚度的减小,能实现的最优阻尼比减小,对应的最优阻尼系数也减小,会影响阻尼器效率;另外,各阶模态的无量纲阻尼比曲线不一致,不能采用统一的无量纲阻尼比曲线来设计阻尼器参数;阻尼器支架的模态质量对阻尼器效率影响很小.

Numerical Investigation on Influence of Damper Support Stiffness on Damping Effect of Suspension Bridge Hangers

The influence of the damper support stiffness on the damping effect of suspension bridge hangers was studied by means of numerical method. Firstly, governing equations of the support-damper-hanger system were established by simplifying the damper support as a spring-oscillator model. Secondly, the discontinuous Dirac Function in the governing equations was approximately handled to adapt the Finite Difference Method (FDM) utilized in this paper, and the governing equations of the support-damper-hanger system were numerically solved by FDM. The effect of the damper stiffness on the dimensionless curve of damping ratio, realizable maximum damping ratio and its corresponding damping coefficient, as well as mass of damper support was carefully studied. The results obtained in this paper agree well to the literature results. The results also show that the realizable maximum damping ratio and its corresponding optimal damping coefficient decrease with the decrease of the damper support stiffness, which affects the efficiency of the damper. As the dimensionless curves related to the damping ratio exhibit obvious differences at each mode, it is impossible to use a Universal Curve related to modal damping ratio to design the damper parameters. In addition, the mass of the damper support has little influence on the damping ratio.