基于特征系统实现算法的输电塔气动阻尼风洞试验研究  

Wind tunnel tests for aerodynamic damping of a transmission tower based on eigensystem realization algorithm

作　　者：段成荫[1] 邓洪洲[1] 

机构地区：[1]同济大学建筑工程系,上海200092

出　　处：《振动与冲击》2014年第21期131-136,147,共7页Journal of Vibration and Shock

摘　　要：为研究输电塔结构环境激励下的气动性能,采用特征系统实现算法(ERA)对风洞试验结果进行模态参数识别,提出表征各阶模态脉冲响应振幅的模态参与因子(MPF)作为识别系统模态的参数,利用各阶模态参与因子和相应的特征值推导了模态能量贡献(MEC)的估算公式,利用模态参与因子和模态能量贡献自动提取系统模态以减小识别中的主观影响。比较了试验结果与准定常理论的异同,讨论了气动阻尼与平均风速和风向的关系。结果表明输电塔结构气动阻尼多为正阻尼,顺风向随风速的增大而增大,横风向基本保持定值且未出现负阻尼,气动阻尼与平均风速分量之间存在非线性关系,因而在准定常理论基础上通过引入高阶项对试验结果进行了拟合。A wind tunnel test was conducted to investigate the aerodynamic behavior of a transmission tower subjected to ambient excitation and the eigensystem realization algorithm was employed to identify the modal parameters of the tower from the wind tunnel test results.The concept of modal participation factor （MPF） was introduced,it represented the impulse response amplitude of each mode therefore was an indicator to discriminate system modes from noise.Then the modal energy contribution （MEC）of each mode was deduced on the basis of MPF and the corresponding eigenvalue.With the aid of MPF and MEC,an auto identification scheme was applied to minimize the subjective influence on modal parameter identification.The test results were examined in a variety of wind speeds and wind attack angles,the test results were compared with the theoretical values derived from the quasi-steady assumption.The results showed that the aerodynamic damping ratios of the transmission tower are generally positive;the longitudinal aerodynamic damping increases with increase in wind speed,while in lateral direction no clear trend is observed;there is a nonlinear dependency of aerodynamic damping ratio on mean wind speed therefore the quasi-steady assumption is adjusted by introducing higher-order terms of wind speed.

关 键 词：输电塔 气动阻尼 风洞试验 特征系统实现算法 模态参与因子 模态能量贡献 

分 类 号：TM753[电气工程—电力系统及自动化] TU317.1[建筑科学—结构工程]