Nonlinear dynamic response of stay cables under axial harmonic excitation

This paper proposes a new numerical simulation method for analyzing the parametric vibration of stay cables based on the theory of nonlinear dynamic response of structures under the asynchronous support excitation. The effects of important pa- rameters related to parametric vibration of cables, i.e., characteristics of structure, excitation frequency, excitation amplitude, damping effect of the air and the viscous damping coefficient of the cables, were investigated by using the proposed method for the cables with significant length difference as examples. The analysis results show that nonlinear finite element method is a powerful technique in analyzing the parametric vibration of cables, the behavior of parametric vibration of the two cables with different Irvine parameters has similar properties, the amplitudes of parametric vibration of cables are related to the frequency and amplitude of harmonic support excitations and the effect of distributed viscous damping on parametric vibration of the cables is very small.

斜拉索阻尼特性的试验研究

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。