平面张弦梁结构风致响应的频域分析

采用频域分析法对一工程实例平面张弦梁结构进行了风致响应分析，并重点讨论了直接影响计算结果的一些主要参数，包括参与组合的振型数量、振型耦合项的取舍、相关函数的选择和结构阻尼比．研究表明．组合振型数在10阶以内取值时，计算结果的差异很大，大于10阶取值时，差异很小，并且当大于20阶时，这种差异微平其微，故组合振型数应取10阶到20阶之间为宜；振型耦合项的取舍对结构两端部的影响较小，对跨中部位的影响较大，最大差异达到14．3％；采用与频率有关的相干函数比无关的相干函数计算得到的结果偏大，最大差异可达224％；采用不同的阻尼比所造成的计算结果的差异很小，仅在4％以内；此外，频域法与时域法相比，计算结果偏大．

Frequency Domain Analysis of Wind-Induced Vibration Response of Plane Beam String Structure

The frequency domain method was used for the analysis of wind-induced vibration of a plane beam string struc-ture(BSS),and some major parameters which influence the results directly including the number of contributing modes,coupling terms between modes,coherence function and structural damping ratio were discussed.The research indicates that results with difference number of contributing modes are very different while the number of contributing modes is within 10,the difference is small while the number of contributing modes is more than 10,and the difference can be ignored while the number of contributing modes is more than 20,so the number of contributing modes should be between 10 and 20.The influ-ence of coupling terms between modes on the structure is small at the two ends,while it is big in the middle part,and with and without the coupling terms between modes,the biggest difference is 14.3%.The result with coherence function relevant to frequency is bigger than that with coherence function irrelevant to frequency,the biggest difference is 22.4%.The influ-ence of damping ratio is small,the biggest difference is less than 4%.Moreover,compared with the time domain method,the result of the frequency domain method is bigger.