利用球形弹簧摆对输电塔风振控制的有限质点法

Finite particle method for wind-induced vibration control of transmission towers with spherical spring pendulum

为了研究球形弹簧摆对输电塔结构的风致振动控制效果,通过分段等刚度梁单元建立输电塔简化模型。给出了空间梁系结构基于Timoshenko梁理论的单元内力计算公式,并应用有限质点法对简化模型及其与球形弹簧摆的耦合系统进行风致响应分析。一方面,球形弹簧摆由于内共振性质实现非线性能量阱,从而增加振动抑制频带的宽度,提高了鲁棒性;另一方面,球形弹簧摆和结构的非线性耦合,使得顺风向的振动能量部分转移到横风向,尽管增大了横风向响应,但是降低了结构的总体响应。计算结果表明球形弹簧摆减振效果非常好,当将其安装在除塔顶外的三个位置时,位移最大值和加速度均方根减振率分别为32.5%~41.7%和35.7%~65.2%。保持质量比和安装位置不变,验证了球形弹簧摆具有较宽的设计频带。使用球形弹簧摆可以显著减小位移标准差,有利于降低结构的疲劳损伤风险。

In order to study control effect of spherical spring pendulum on wind-induced vibration of transmission towers,a reduced model of transmission tower was established with segmental isostiffness beam elements.The element interal force calculation formula based on Timoshenko beam theory for spatial beam structrues was derived.The wind-induced responses of the reduced model and the reduced model-spherical spring pendulum coupled system were analyzed with the finite particle method,respectively.On one hand,due to internal resonance property,the spherical spring pendulum realized a nonlinear energy sink to increase the frequency band width of vibration suppression and improve the robustness.On the other hand,because of nonlinear coupling between the spherical spring pendulum and the reduced model,vibration energy in wind direction was transferred to that in transverse wind direction.Although the system response in transverse wind increased,the overall response of the system decreased.The calculation results showed that the vibration reduction effect of spherical spring pendulum is excellent;when it is installed at 3 positions except tower top,vibration reduction rates for the maxium displacement and the acceleration root mean square are in ranges of 32.5%-42.5% and 35.7%-65.2%,respectively;if keeping mass ratio and installation position unchanged,spherical spring pendulum has a wider design frequency band;using spherical spring pendulum can significantly reduce standard deviation of displacements so as to reduce fatigue damage risk of structures.