覆冰输电线路舞动气动阻尼识别  

Aerodynamic damping identification for iced transmission line galloping

作　　者：王昕[1] 楼文娟[1] 沈国辉[1] 

机构地区：[1]浙江大学结构工程研究所,杭州310058

出　　处：《振动与冲击》2011年第10期160-164,共5页Journal of Vibration and Shock

基　　金：国家自然科学基金(51178424)

摘　　要：利用覆冰导线刚性节段模型外加弹簧及配重模拟覆冰输电线路竖向及扭转运动动力特性,制作了D形覆冰单导线、新月形覆冰单导线和分裂导线竖向-扭转二自由度气弹模型,通过调整模型竖向/扭转自振频率比及风速、风攻角,于风洞中激发了D形覆冰单导线气弹模型的纯竖向和竖扭耦合失稳舞动,以及新月形覆冰分裂导线气弹模型的竖扭耦合舞动,并记录了其响应时程,通过Hilbert变换进行了竖向舞动和扭转气动阻尼的识别,研究了风速、风攻角、竖扭频率比、覆冰断面、导线数量及布置形式对气动阻尼的影响。对D形覆冰导线纯竖向舞动时根据响应识别所得气动阻尼比与根据Den-Hartog机理计算所得理论气动阻尼比进行了比较。试验结果表明:舞动时气动阻尼比为负值,在试验风速范围内其绝对值随风速增长而增大;D形覆冰导线纯竖向舞动时识别所得气动阻尼比绝对值略小于理论气动阻尼比;导线分裂数量对气动阻尼具有影响;扭转响应对竖向舞动气动阻尼的影响则较为复杂。Aeroelastic models of single D section iced conductors and bundled crescent section iced conductors were made.The dynamic characteristics of vertical and torsional movement of the conductor models were simulated by adding springs and additional weight.By varying ratio of vertical and torsional natural vibration frequencies of the conductor model,vetical galloping and vertical-torsional coupled galloping of a D section iced conductor,vertical-torsional coupled galloping of a bundled crescent section iced conductor were excited and recorded,respectively in a wind tunnel under appropriate wind speed and attack angles.Vertical and torsional aerodynamic damping in galloping were identified with Hilbert transformation,impacts of wind speed,attack angle,ratio of vertical and torsional natural vibration frequencies,iced profile and number of sub-conductors on aerodynamic damping were studied.The aerodynamic damping identified from vetical galloping of a D-section iced conductor was compared with theoretical Den Hartog aerodynamic one.It was indicated that the aeroelastic model has a negetive aerodynamic damping value,and its magnitude increases with increase in test wind speed;the identified aerodynamic damping of a single D section iced conductor in vertical galloping has slightly lower magnitude than that of the theoretical Den Hartog aerodynamic damping;the number of sub conductors influences aerodynamic damping of bundled conductors with the same iced profile;torsional response has a complicated impact on aerodynamic damping.

关 键 词：舞动 覆冰导线 风洞试验 气动阻尼 

分 类 号：TV352.11[水利工程—水工结构工程]