中文摘要：

基于考虑输电导线垂向和扭转振动耦合的两自由度模型，利用多尺度法和数值分析方法，分别就系统参数和环境参数对临界风速和舞动振幅的影响进行了理论和仿真分析，并讨论了扭转振动分岔导致的可能复杂运动。利用零解的稳定性条件，得到了覆冰厚度、初始覆冰角度、来流密度、导线的初始张力和单位长度质量以及横向阻尼比对临界风速的影响曲线。基于解析和数值仿真的结果，分别给出了风速、覆冰厚度、来流密度、导线的初始张力和单位长度质量以及横向阻尼比对舞动振幅的影响曲线。对扭转振动分岔的研究表明，风速变化时，（零解失稳导致的）周期运动的分岔可导致倍周期运动和概周期运动等复杂运动形式。

英文摘要：

By using the method of multiple scales and numerical simulations, the influence of system parameters and environ- ment parameters on the critical wind speed and the amplitude of galloping, as well as the complex motion resulted from bifur- cation of periodic torsional motion, is investigated based on the 2 DOF model considering the coupling between vertical motion and torsional motion of overhead power transmission lines in this paper. Firstly, the influence of ice thickness, initial ice an- gle, air density, initial tension, mass of unit length and vertical damping ratio on the critical wind speed are given respectively considering the stability condition of the trivial solution of the averaged equations, which is derived according to the Routh- Hurwitz criterion. Then the amplitude of galloping versus wind speed, ice thickness, air density, mass of unit length, vertical damping ratio and initial tension are presented to compare the analytical and numerical results. It is shown that computer simulations are in good agreement with the maximum amplitude predicted by the model. In addition, it is found that, different from the vertical motion, the bifurcation of periodic torsional motion can lead to peroid doubling and quasi-periodic motion with change in wind speed.