树木动力特性的实测和有限元分析研究  

Measurement and finite element analysis of the dynamic characteristics of trees

作　　者：李正农[1] 赵帝 钟旻 吴红华[1] 陈斌 徐海杰 LI Zhengnong;ZHAO Di;ZHONG Min;WU Honghua;CHEN Bin;XU Haijie(Key Laboratory of Building Safely and Energy Efficiency of Ministry of Education,Hunan University,Changsha 410082,China;College of Civil Engineering,Hebei University of Architecture,Zhangjiakou 075000,China)

机构地区：[1]湖南大学建筑安全与节能教育部重点实验室,长沙410082 [2]河北建筑工程学院土木工程学院,河北张家口075000

出　　处：《振动与冲击》2022年第2期271-280,共10页Journal of Vibration and Shock

基　　金：国家自然科学基金(51678233)。

摘　　要：该研究对一棵柳树在力锤激励和自然风激励条件下进行了模态识别与分析,发现力锤激励时的模态识别结果缺失了部分模态,而自然风激励条件下能较好地识别柳树的主要模态。通过综合两种激励下的模态识别结果,确定了柳树实测的前十阶模态。根据实际柳树的形状、采取合理的材料参数,对该柳树构建了有限元分析模型,并进行模态分析,得到了其前十阶自振频率和振型,发现柳树在各阶振型处主要为树枝的振动,而树干振动较小。最后进行了有限元分析结果和实测结果的对比,发现两者间有较好的对应关系,说明柳树有限元模型的构建是正确的,发现柳树的树冠结构对柳树结构动力特性有着巨大的影响。The modal identification and analysis of a willow tree under force hammer excitation and natural wind excitation were carried out,and it is found that part of the modal identification results under force hammer excitation might be missed while the main modes of the willow tree could be better identified under natural wind excitation.Synthesizing the modal identification results under the two types of excitation,the first ten modes of the willow tree were determined.Based on the actual willow shape and reasonable material parameters,a finite element analysis model was constructed for the willow tree,and modal analysis was carried out to obtain the first ten natural vibration frequencies and vibration modes of the willow tree.It is found that the most vibration modes of the willow tree appear mainly as the local vibration of the branches,while the vibration of the trunk is relatively small.Finally,the comparison between the results of the finite element analysis and actual measurement shows that there is a good correspondence between them,which indicates that the construction of the willow finite element model is correct,and the canopy structure of the willow has a great influence on the dynamic characteristics of the whole willow structure.

关 键 词：树木 力锤激励 自然风激励 有限元 动力特性 

分 类 号：Q947.6[生物学—植物学] O327[理学—一般力学与力学基础]