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研究特大悬索桥施工过程中主缆非线性参数振动问题.综合考虑主缆垂度、大变形引起的几何非线性等因素,将桥塔塔顶振动考虑为主缆的参数激励项,利用Newton定律建立的主缆参数振动控制方程,运用Galerkin和多尺度方法对主缆参数振动进行了理论分析,以某悬索桥中的主缆为例,运用有限元程序计算了桥塔的前20阶频率,通过桥塔与主缆的第一阶面内频率匹配,0号桥塔的第11,13阶振动及3号桥塔的第4阶振动激发主缆参数振动的可能性最大,数值分析了主缆发生参数振动时的位移时间历程和索力变化规律.研究结果表明,当桥塔的局部振动频率约为主缆振动频率的2倍左右时,主缆容易发生参数振动,发生参数振动时,位移响应显著,缆索张力增量很小.
In this paper, the nonlinear vibration of main cable during the construction of large suspension bridge is studied. Considering the factors such as the main cable sag and the geometric nonlinearity caused by large deformation, the top vibration of the bridge tower is considered as the parametric excitation of the main cable, which is established by Newton’s law The main cable parameters vibration control equations are analyzed by using Galerkin and multi-scale methods. Taking the main cable in a suspension bridge as an example, the top 20 frequencies of the tower are calculated by the finite element program. The first-order in-plane frequency matching between the tower and the main cable, the 11th and 13th-order vibration of the No. 0 tower and the 4th-order vibration of the No. 3 tower are most likely to vibrate. The main cable is analyzed numerically The time history of displacements and the variation regularity of cable force when the parameters vibrate.The results show that when the local vibration frequency of the bridge tower is about two times of the vibration frequency of the main cable, the main cable is prone to parametric vibration. When the parametric vibration occurs, the displacement response Significantly, the cable tension increase is small.