基于新型轴向电涡流阻尼器的拉索多模态减振性能研究

The performance of cable’s multi-mode vibration control based on an eddy current damper

研究了新型滚珠丝杠式轴向电涡流阻尼器(ball screw type axial eddy current damper,BS-ECD)对拉索的多模态减振控制效果。首先,基于单位振动周期内耗能相等的原则计算了BS-ECD等效线性阻尼系数的表达式。然后,利用等效线性化理论推导了安装BS-ECD后拉索附加模态阻尼比的表达式。以此为基础,针对拉索多模态振动控制开展了BS-ECD的参数优化设计,得到了拉索受控模态分别为1~4阶和1~8阶时BS-ECD的最优临界速度、峰值阻尼力和拉索附加模态阻尼比,并评价了其减振性能。最后,分析了减振效果对阻尼器最优参数和位移幅值变化的敏感性。分析结果表明:存在一组BS-ECD的临界速度和峰值阻尼力,可以使拉索任意两阶模态的附加阻尼比同时达到最大值;当指定阻尼器工作行程时,通过参数优化可以使BS-ECD的多模态减振效果优于线性黏滞阻尼器和非线性液体黏滞阻尼器,且减振效果对最优参数变化不敏感;与其他非线性阻尼器一样,BS-ECD提供的附加模态阻尼比也具有明显的振幅依赖性,当阻尼器的工作行程偏离设计值时,其减振效果会有较明显的降低,后续应仔细研究。

The performance of a new type of ball screw type axial eddy current damper(BS-ECD)on cable’s multi-mode vibration control was investigated.Firstly,the expression of BS-ECD’s equivalent linear damping coefficient was calculated based on the equal energy dissipation in every vibration period,and then the expression of the cable’s additional modal damping ratio after installing the BS-ECD was derived by using the equivalent linearization theory.Based on this,the BS-ECD’s parameter optimization was carried out for the cable’s multi-mode vibration control.Meanwhile,the BS-ECD’s optimal critical speed and peak damping force as well as the cable’s additional modal damping ratio were obtained when the interested modes in the cable focus on 1-4 and 1-8,and the BS-ECD’s vibration control performance was evaluated based on these optimal parameters.Finally,the sensitivity of BS-ECD’s optimal parameters and displacement amplitude of damper’s location towards damper’s control performance was analyzed.The results show that there is a set of BS-ECD parameters,which can make any two modes of the cable’s additional damping ratio reach the maximum at the same time.When the working stroke of the damper is specified,BS-ECD’s performance in cable’s multi-mode vibration control is better than both linear viscous dampers and nonlinear liquid viscous dampers counterparts after optimization and BS-ECD’s control performance is not sensitive to optimal parameters’deviation.Like other nonlinear dampers,the BS-ECD’s additional modal damping ratio is also dependent on amplitude obviously.When the working stroke of the damper deviates from the design value,its damping effect will be significantly reduced,which should be carefully studied in the follow-ups.