自供电MR阻尼器对斜拉索减振的试验研究

Experimental study on cable vibration control with a self-powered MR damper

为简化磁流变(MR)阻尼器斜拉索减振系统,同时提高可靠性,基于电磁式振动能量回收技术构建了具有自供电特性的MR阻尼器斜拉索减振系统。其主要由分别安装在拉索较低、较高位置的电流调节式MR阻尼器、旋转式永磁发电机构成,采用链条-链轮机构进行斜拉索面内往复直线运动与电机转子旋转运动的转化,将电机回收的振动能量直接作为MR阻尼器的电源。模型斜拉索减振试验结果表明:相对外供电MR阻尼器最优被动控制,自供电MR阻尼器除斜拉索第1阶模态减振效果基本相当外,自供电MR阻尼器对斜拉索第2~4阶模态减振效果突出,相应的模态阻尼比分别提高了31.8%、37.4%与43.0%;随着斜拉索模态阶次的逐渐增大,自供电MR阻尼器的负刚度控制特性越加凸显,从而显著提高了自供电MR阻尼器对斜拉索高阶模态的减振效果。

To simplify cable vibration control system with MR dampers and enhance its reliability, a self-powered MR damper vibration control system for stay cables based on electromagnetic vibration energy harvesting is proposed. The system consists of a current-adjusted MR damper attached at a low position of the cable, a rotary permanent magnet generator attached at a relatively higher position of the cable as well as a roller chain and sprocket for linear-to-rotational conversion from vertical vibration of the cable to rotation of the generator rotor. The electromotive force generated by the generator is directly used to provide power supply to the MR damper. Model cable test results shows that the developed self-powered MR damper can greatly improve modal damping ratios in each of first four modes of the test cable, and it can provide increased modal damping ratios from the second mode of the cable with respect to an optimum passively operated MR damper. The modal damping ratios are improved at 31.8%, 37.4% and 43.0% for the 2nd, 3rd and 4th mode of the cable, respectively. Moreover, the self- powered MR damper can realize negative stiffness control characteristics from the second mode of the cable, and the higher mode number, the more significant negative stiffness.