应用油阻尼器的斜拉索实索减振试验研究

应用一种国产油阻尼器进行了斜拉索实索减振试验研究。通过自由振动衰减曲线计算得到了拉索-油阻尼器系统前3阶模态的对数衰减率值。试验结果表明拉索的内阻尼很小,对数衰减率均值小于0.005,频率值则与理论计算值很接近。安装油阻尼器后拉索前3阶模态的对数衰减率均值达到了0.03以上,表明油阻尼器可有效抑制拉索的振动,拉索的频率在安装阻尼器后稍有增大。试验实测得到连接油阻尼器后拉索的对数衰减率值要小于理论计算值,导致这一差异的原因是由于阻尼器支架连接刚度、阻尼器连接件空隙的影响。因此,必须对拉索减振工程中阻尼器支架和连接件的设计安装予以重视。

A Full-scale Cable Vibration Mitigation Experiment by Using Oil Damper

A full-scale cable vibration mitigation experiment was conducted by using a 215 meters long stay-cable and a set of oil dampers.The logarithmic decrement of the first three modes of the cable-damper system was calculated from free vibration decay curve.It is found that,the internal damping of the cable is very low,the mean logarithmic decrement is lower than 0.005,and the frequency is near to the analytical one;the derived mean value of logarithmic decrement of cable-damper system is larger than 0.03,which mean that the oil damper is effective to suppress cable vibration,and the tested frequeney of cable-damper system is a bit larger than that of the free cable. The logarithmic decrement of cable-damper system measured from experiment is less than the analytical one,due to the supporter stiffness and the gap in joint.It should pay attention to the supporter stiffness and the installation of oil damper for implementation of oil damper for cable vibration mitigation.