刚性吊杆-水平抗风索耦合系统弯曲振动自振特性分析  

Free flexural vibration characteristics analysis of a rigid hanger-horizontal wind resistant cables coupled system

作　　者：赵洋[1,2] 徐凯[2] 汪志昊[2] 陈惟珍[1] Zhao Yang Xu Kai Wang ZhiHao Chen WeiZhen(Department of Bridge Engineering, Tong Ji University, Shanghai 200092, China School of Civil Engineering and Communication, North China University of Water Resources and Electric Power, Zhengzhou 450011, China)

机构地区：[1]同济大学桥梁工程系,上海200092 [2]华北水利水电大学土木与交通学院,郑州450011

出　　处：《振动与冲击》2017年第11期92-99,110,共9页Journal of Vibration and Shock

基　　金：国家自然科学基金(51308214);国家重点基础研究973计划(2015CB057702);河南省教育厅科学技术研究重点项目(13A560711);河南省高校科技创新团队支持计划(15IRTSTHN028);河南省高等学校青年骨干教师资助计划(2015GGJS-104)

摘　　要：将1对水平抗风索对钢拱桥刚性吊杆的约束作用简化为4个水平弹簧支撑,推导了抗风索等效弹簧刚度计算公式;基于欧拉-伯努利连续梁理论与吊杆-水平抗风索连接位置处的相容连续性条件,建立了刚性吊杆-水平抗风索耦合系统弯曲振动自振特性分析理论模型,通过与有限元结果对比验证了该方法的准确性;明确了水平抗风索位置、刚度参数对H型、矩形刚性吊杆纵桥向弱轴弯曲振动自振特性的影响规律。研究结果表明:合理设计的抗风索对H型、矩形刚性吊杆弱轴弯曲基频均有较大程度的提升,证实了抗风索对刚性吊杆弯曲模态减振的可行性;抗风索位置不同,对吊杆弱轴弯曲基频的影响程度也不同,且位置参数直接决定了吊杆弯曲基频增长极限值;相对H型吊杆,附加抗风索的矩形吊杆弱轴弯曲基频提升潜力更大。研究成果对钢拱桥刚性吊杆弯曲模态振动控制的水平抗风索减振参数优化设计具有重要参考价值。The restriction effect generated by a pair of horizontal wind-resistant cables on a hanger were simplified as four equivalent springs. On this basis, the formula for equivalent stiffness generated by wind-resistant cables was deduced. Based on Bernoulli-Euler beam theory and compatibility conditions of a hanger on the connection with horizontal wind-resistant cables, a theoretical analysis model for free flexural vibration characteristics of a hanger coupled with horizontal wind-resistant cables was established. The accuracy of the theoretical model was then verified by finite element methods. Finally, the effects of locations and stiffness of horizontal wind-resistant cables on weak-axis flexural vibration characteristics of H-Section and rectangular rigid hangers were well investigated. It is shown that the fundamental weak-axis flexural frequencies of hangers are greatly enhanced by appropriate wind-resistant cables, which indicates that the wind-resistant cables are also feasible for flexural vibration control of rigid hangers. The incidence effect of wind-resistant cables on fundamental flexural frequencies of a hanger is not the same with different locations of wind-resistant cables, and the ultimate flexural frequencies of a hanger are directly determined by the location of wind-resistant cables. Comparing with H-Section hangers, rectangular hangers coupled with wind-resistant cables have more potential for promoting its first-order weak-axis flexural frequencies. The research results provide a valuable theoretical base for flexural vibration mitigation design of rigid hangers with horizontal wind-resistant cables.

关 键 词：刚性吊杆 水平抗风索 等效弹簧 弯曲振动 自振频率 振型 

分 类 号：TU311.3[建筑科学—结构工程]