MR阻尼器对斜拉索被动控制的研究

STAY-CABLE PASSIVE CONTROL USING MR DAMPERS

由于斜拉索引入MR阻尼器后构成的系统具有非线性, 无法采用求解特征值的方法来评价MR阻尼器对斜拉索的减振效果。本文以全索全时段振动响应的均方根(RMS) 作为评价指标, 研究了MR阻尼器的最优型号与阻尼器安装位置、施加的电压、斜拉索基频(张力、索长、质量)、激励荷载(类型、频率、大小) 等各种因素的关系, 并与最优粘性油阻尼器进行了比较。最优的MR阻尼器被动控制效果与最优粘性油阻尼器被动控制效果相当; 制振频域比粘性油阻尼器宽广, 更能适应外界荷载多变的情况; 电压失效时也能提供较大的系统等效阻尼比。

A stay cable incorporated with MR dampers exhibits pronounced nonlinearity. The dynamic performances of a cable with MR dampers are explored in detail by using the Spencer phenomenological model. The primary measure of damper performance considered is the Root Mean Square (RMS) cable deflection integrated along the length of the cable and for the whole period of time. The relationship between the optimal marker of the MR dampers, the mounting postion, the voltage applied, the first frequency of the cables (tensile force, length,and mass per unit length), and the exciting loads (type, frequency,and amount)are studied. The mitigation effect of the MR dampers is about the same as that of the optimal oil dampers. It is shown that the MR damper is a type of passive control device,and can offer comparatively large equivalent damping ratios without applied voltage. The dynamic range of MR dampers is sufficiently wide, and can be more effective in first three frequency modes than oil dampers do.