电磁惯质阻尼器对超长斜拉索的减振性能分析

Vibration Mitigation Performance Analysis of Electromagnetic Inertial Mass Damper for Super-long Stay Cables

电磁惯质阻尼器是一种新型高性能被动阻尼器。在斜拉索减振应用中,电磁惯质阻尼器不仅可给斜拉索提供电磁阻尼力,也可提供与加速度成正比的惯性力,因此其可实现很大的附加质量效应,从而极大地提升斜拉索减振性能。本文以我国香港昂船洲大桥一根长307 m的超长索为对象,通过数值模拟的方法系统地研究了电磁惯质阻尼器对斜拉索低阶和高阶模态的减振性能。本文建立了斜拉索-电磁惯质阻尼器系统的有限差分模型;进行了特征值分析以确定各阶模态的电磁惯质阻尼器最优参数;并分析了在简谐激励和抖振力激励下,其对斜拉索的减振性能。结果表明,与线性粘滞阻尼器相比,电磁惯质阻尼器对斜拉索系统模态阻尼比的提升约为10倍,并且在上述两种激励下,斜拉索的响应控制效果均优于粘滞阻尼器。

Electromagnetic inertial mass damper(EIMD)is a novel type of passive damper and has superior performance in vibration control.In the application of stay cable vibration reduction,electromagnetic inertial mass damper can not only provide electromagnetic damping force to stay cable,but also provide inertial force proportional to acceleration.Therefore,it can achieve great additional mass effect and greatly improve the vibration mitigation performance of stay cables.In this paper,a 307 m long super long cable of stonecutters bridge in Hong Kong is taken as an example to study systematically the vibration mitigation performance of low and high modes of stay cables with electromagnetic inertial mass damper by numerical simulation.In this paper,a finite difference model of the cable-stayed electromagnetic inertial damper system is established;the eigenvalue analysis is carried out to determine the optimal parameters of the electromagnetic inertial mass damper in each mode;and the vibration mitigation performance of the cable under harmonic excitation and buffeting force excitation is analyzed.The results show that compared with the linear viscous damper,the modal damping ratio of the cable system is increased by ten times by the electromagnetic inertial mass damper,and the response control effect of the cable under the above two excitations is better than that of the viscous damper.