覆冰导线三自由度耦合舞动稳定性判定及气动阻尼研究

发布时间：2018-04-10 12:34

本文选题：舞动 + 覆冰导线　；参考：《土木工程学报》2017年02期

【摘要】：利用风洞内支架式三自由度频率可调的弹簧悬挂装置对D形覆冰六分裂导线节段气弹模型进行舞动试验,在不同气动力特性的风攻角下调整竖/扭自振频率比及风速,激发并记录纯竖向、纯扭转、竖扭耦合和扭转水平耦合等失稳舞动。分别基于实测响应和三自由度舞动响应非线性数值模拟结果识别导线的竖向和扭转气动阻尼并与Den Hartog或Nigol舞动理论计算值进行对比,研究导线气动阻尼与气动特性、自振特性及风速之间的关系。试验结果发现:由于Den Hartog或Nigol系数正负不同以及竖/扭频率比不同,导线气动负阻尼绝对值会随风速提高以指数形式增大或者是随风速提高先增大后减小至小于结构阻尼;用单自由度舞动理论来预测三自由度舞动存在较大缺陷且偏于不安全。基于特征值摄动法提出覆冰分裂导线竖向-水平-扭转三自由度耦合的舞动稳定性判断条件式,解释了无法用Den Hartog或Nigol单自由度稳定性判断条件式说明的舞动现象,并得到试验结果的验证。
[Abstract]:In this paper, the three-degree-of-freedom spring suspension device with support in wind tunnel is used to perform galloping test on D-shaped ice-coated six-split conductor segment Aeroelastic model. The vertical / torsional natural vibration frequency ratio and wind speed are adjusted under different attack angles of aerodynamic characteristics.Excitation and recording of pure vertical, pure torsion, vertical torsional coupling and torsional horizontal coupling instability dance.The vertical and torsional aerodynamic damping of conductors are identified based on the results of nonlinear numerical simulation of measured responses and three-degree-of-freedom galloping responses, and compared with the calculated values of Den Hartog or Nigol galloping theory, the aerodynamic damping and aerodynamic characteristics of conductors are studied.The relationship between natural vibration characteristics and wind speed.The experimental results show that due to the difference of Den Hartog or Nigol coefficients and the ratio of vertical / torsional frequency, the absolute value of aerodynamic negative damping of conductors increases exponentially with the increase of wind speed or decreases to less than the structural damping at first and then decreases with the increase of wind speed.The theory of single degree of freedom is used to predict that the three degree of freedom galloping has great defects and is not safe.Based on the eigenvalue perturbation method, a condition for judging the galloping stability of ice-coated split conductors coupled with vertical, horizontal and torsional three degrees of freedom is presented, which explains the galloping phenomenon which can not be explained by Den Hartog or Nigol single degree of freedom stability judgment condition.The experimental results are verified.
【作者单位】：浙江大学结构工程研究所;河南省电力试验研究院;
【基金】：国家自然科学基金面上项目(51178424,51378468)
【分类号】：TM752

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