用于阻尼器试验的斜拉索等效模型建模

EQUIVALENT MODEL OF STAY CABLE WITH A DAMPER FOR EXPERIMENTAL STUDY

该文提出一种便于试验室内布置的短梁模型等效斜拉索,利用该模型可进行足尺拉索阻尼器试验研究。等效原则为,附加阻尼器后等效模型一阶振动频率及模态阻尼与其原型按张紧弦理论计算得到的相应值相等。该文首先提出了等效模型的概念及参数;然后,对比水平张紧弦-线性粘滞阻尼器系统的振动分析理论,对等效模型进行了自由振动和有阻尼振动的参数分析,采用数值方法分析了模型的振动特性;最后比较模型与原型的振动特性,提出确定模型参数的方法。数值模拟结果表明:按上述方法得到的等效模型与原型一阶振动频率及附加相同阻尼器后模态阻尼比的差值均小于5%,等效模型具有良好的精度。

An equivalent model with short length, which could be set in laboratory, is proposed for experiment studies on cable vibration control. The equivalent model attached with a full scale damper aims to simulate behaviors of a damped stay-cable interpreted by taut cable-linear viscous damper theory. Specifically, with the same optimal damper, the equivalent model can achieve the same natural frequency and modal damping as those calculated by taut cable theory for a full scale cable-damper system. Firstly, the model and relevant parameters are proposed by a conceptual analysis; then taut cable-linear viscous damper theory is reviewed, and the parameter analysis is carried out to explore the dynamics characteristics of the model, where numerical method is applied; finally, by comparing the dynamic characteristics of the taut cable and equivalent model, a designing approach is derived. As the verification, the simulation of a cable and its equivalent model are conducted via the finite element method and results illustrate that the errors of the frequency and modal damping ratio are less than 5%, indicating the equivalence.