大跨越导线微风振动波的色散关系分析

Dispersion Analysis on Aeolian Vibration Wave of Long-span Conductors

为探索大跨越导线微风振动特性,在合理假设的基础上建立了导线横向微风振动的一般方程,从振动波的角度,分析了典型导线结构模型的复波数、相速度与频率之间的色散关系以及弹性刚度和阻尼对振动波的影响特性。研究结果表明:弹性刚度决定了激励频率能否引起导线振动波的传播,当激励频率大于临界频率时,弦模型导线的振动波为两列方向相反的传播行波;传播过程中各阶频率相速度主要由结构参数张力和线密度确定,弹性刚度使振动波中低频波传播速度快而高频波相速度基本一致,具有明显色散现象;阻尼决定了振动波在传播过程中的衰减特性,对结构的色散现象影响不大。

To study the characteristics of aeolian vibration of long-span conductors,this paper established a general equation for a damped tensioned string on an elastic foundation from reasonable assumptions.From the perspective of vibration waves,it analyzed the dispersion relation among complex wave number,phase velocity and frequency of typical conductor structure models.It also analyzed the influence of damping and elastic stiffness on vibration waves.The results show that elastic stiffness is key in the wave propagation caused by disturbance frequency.When disturbance frequency is greater than critical frequency,there appear two waves traveling in opposite directions.In the wave propagation,frequency phase velocities of each order are mainly determined by structural parameters tension and linear density.The elastic stiffness presents dispersion phenomenon that the phase speed of the low-frequency wave is fast,while the phase speed of high-frequency wave is identical basically.Damping determines the attenuation characteristics of vibration waves during propagation and has little influence on structural dispersion phenomenon.