基于曲梁理论的覆冰分裂导线舞动非线性动力分析

Nonlinear Dynamic Analysis of Galloping of Iced Bundle Conductor Based on Curved Beam Theory

基于空间曲梁理论的应变-位移关系,建立了具有三个平动自由度和一个转角自由度的覆冰分裂导线舞动分析混合模型.考虑覆冰导线所受空气动力的非线性和导线大幅运动的几何非线性,利用虚功原理建立覆冰分裂导线的非线性动力学方程.采用振型叠加法将方程变换到振型空间中,并使用时间积分算法求解.然后通过数值计算对单元无关性进行了检验,分析单元数量对覆冰导线前六阶频率的影响;此外研究了模态收敛性,分析模态截断对舞动响应的影响;最后分析了气动力对结构频率的影响.研究结果表明,气动力对分裂导线的扭转频率有较大的影响,这准确地反映了输电线路的动态特性;另外,覆冰分裂导线混合模型用于输电线的舞动分析时具有可靠的精度,说明该混合模型可以预测输电线路的实际舞动响应,便于后续控制设计的实施.

Based on the strain-displacement relationship of the spatial curved beam theory,a hybrid model for galloping analysis of iced bundle conductors with three translational degrees of freedom and one rotational degree of freedom is established.Considering the aerodynamic force nonlinearity and the geometric nonlinearity of the large amplitude motion for the iced conductor,the nonlinear dynamic equation of the iced bundle conductors is established with the virtual work principle.The equation is transformed into the sub-space according to the mode superposition method and solved by the time integration algorithm.Then,the element independence is verified by numerical calculation,and the influence of the number of elements on the first six frequencies of iced conductors is analyzed.Furthermore,the modal convergence is studied,and the effect of modal truncation on galloping response is analyzed.Finally,the influence of aerodynamic force on structural frequency is analyzed.The results show that the aerodynamic force has a significant effect on the torsional frequency of the bundle conductor,which accurately reflects the dynamic characteristics of the transmission line.On the other hand,the hybrid model of iced bundle conductors has reliable accuracy in calculating the galloping analysis of transmission lines,indicating that the hybrid model can predict the actual galloping response of transmission lines and facilitate the implementation of subsequent control design.