斜拉索阻尼特性的试验研究

Experimental Investigation on Damping Characteristics of Stay Cables

斜拉索是桥梁和其它结构中的常用构件,其阻尼特性对于计算缆索结构在各种载荷作用下的动力响应具有重要意义。本文对1根长为143m的斜拉索按照比例12:1制作了比例模型并对其进行试验研究,测定了比例模型在4种张力水平下的前6阶面内及出面模态、固有频率和相应的模态阻尼。采用复合阻尼模型对模态阻尼进行拟合,获得了良好的效果。用有限元法建立了斜拉索的计算模型,计算所得频率、模态和试验结果取得很好的一致。

This paper describes the internal damping testing of a cable model scaled down from a 143m - long prototype cable in an actual cable structure. The natural frequencies, mode shapes and modal damping ratios of the first six in - plane modes as well as the first six out - of - plane modes under four different tension force lev-els are experimentally determined. The experimentally obtained natural frequencies and mode shapes of the concerned modes agree well with those from analytical methods. The modal damping of the out - of - plane modes is found dependent on cable tension and can be accurately described by the combined Rayleigh and frequency - in-dependent damping (CRFID) model.