考虑脉动风影响的斜拉索在支点激励下的非线性振动  

Nonlinear vibration of stay cables under fluctuating wind load and support excitation

作　　者：谢旭[1] 张治成[1] 中村一史[2] 前田研一[2] 

机构地区：[1]浙江大学,浙江杭州310058 [2]日本首都大学,东京192-0397

出　　处：《土木工程学报》2008年第12期66-72,共7页China Civil Engineering Journal

基　　金：国家自然科学基金(50578141)

摘　　要：应用柔性拉索的非线性振动响应计算理论,提出考虑横向脉动风荷载作用及支点激励的拉索非线性振动计算方法。以力学特性不同的两种斜拉索为对象,通过数值方法分析横风作用和支点激励下的钢索、CFRP拉索非线性振动响应,比较支点激励频率、风速、阻尼器对参数振动响应的影响。结果表明,在拉索基频f1以及两倍基频2f1的支点位移激励下,脉动风虽然导致拉索出现不规则的竖向和横向水平振动轨迹,但不会改变拉索的参数振动特性;横向风荷载对参数振动具有空气阻尼力的效应;总体上CFRP拉索的参数振动振幅小于钢索,特别当拉索跨度比较大时,CFRP拉索的振幅将明显低于同跨度的钢索;黏性阻尼装置的减振效果与拉索的结构条件有关,当拉索的无量纲参数λ(Irvine参数)较大时,阻尼器的减振效果不明显,反之当λ较小时阻尼器有一定的减振效果。Based on the nonlinear vibration theory for flexible cables, a numerical method was proposed for calculation of the nonlinear vibration of stay cables due to support excitations and fluctuating wind loads. Two groups of cables with different mechanical characteristics were studied. The dynamic responses of cables subject to lateral wind loads and support excitations were calculated using the numerical method, and the effects of support excitation frequency, wind speed, and dampers on the parametric vibrations of steel and CFRP cables were compared. The results indicate： irregularity occurs in vertical and lateral vibrations of cables under the action of fluctuating wind loads and support excitations with frequencies of the cable＇ s basic frequency f1 or 2f1, but the characteristics of parametric vibration are not affected; the lateral wind has damping effect on parameter vibration of the cable; and the parameter vibration amplitude of CFRP cables are smaller than that of steel ones, and in particular, if the cable spans are relatively larger, the vibration amplitude of CFRP cable will be smaller than that of steel cables. The effect of viscous dampers as related to the physical properties of cables is not so obvious when the dimensionless parameter λ （Irvine parameter） is large, but is more obvious when λ is small.

关 键 词：斜拉索 参数振动 非线性振动 脉动风荷载 CFRP索 

分 类 号：U448.27[建筑科学—桥梁与隧道工程]