采用摩擦型阻尼器的斜拉索被动控制

研究了较常用的线性粘滞阻尼器具有更高附加阻尼的非线性摩擦型阻尼器的斜拉索振动控制.首先通过单自由度系统详细分析了摩擦型阻尼器的非线性阻尼特性.进而采用张紧弦模型模拟斜拉索,通过Galerkin方法建立了斜拉索-摩擦型阻尼器系统的运动方程.采用半解析半数值方法分析了斜拉索自由振动的阻尼特性,对其阻尼机理进行了讨论.通过对拉索模态阻尼比的参数分析,得到了阻尼器参数和拉索附加阻尼关系的通用设计曲线,并与已有实索试验结果进行了比较,两者吻合良好.研究了摩擦型阻尼器的参数优化取值,结果表明拉索的最大模态阻尼比依振动初始条件等参数影响分布在一个范围而非定值,其下限值仍高于采用线性粘滞阻尼器时所获得的最大模态阻尼比.

Passive Control of Stay Cable Using Nonlinear Friction Damper

Passive control of stay cable using nonlinear friction damper were studied. A friction damper can provide higher additional damping to stay cable than that of a common linear viscous damper. The damping performance of a single degree of freedom system with a friction damper was investigated. The equation of motion of a taut cable with a coulomb friction damper was derived and was solved by using Galerkin formulation. The free vibration attenuation characteristics and the damping performance of the cable with a friction damper were theoretically and numerically investigated. The damping mechanism was discussed. A universal estimation curve was proposed that relates the modal damping ratio of a cable with a friction damper when the effect of various parameters on damping was considered. The results of numerical simulation were compared with the experiments, they are in good agreement. The value of a maximum available additional damping was analyzed. The results show that the maximum modal damping ratio of cable with a friction damper is not a fixed value, but a range, the lowest value of which is larger than that of an optimal passive linear viscous damper.