适用空间网格结构模态识别的改进功率谱峰值法

Improved power spectrum peak method applied in the modal identification of spatial lattice structures

根据空间网格结构模态密集特点,对传统功率谱峰值法进行改进。提出在获得所有测点平均正则化功率谱基础上,结合结构的理论振型特点计算辅助正则化功率谱,取两者并集为模态识别结果的方法,讨论有关判断准则。改进的功率谱峰值法可更好地避免模态遗漏及进行重叠频率的筛选,网架模型算例表明效果良好。并将编制的分析软件应用于深圳大运会主场馆振动监测系统中。

The traditional power spectrum density peak method was improved according to the feature of dense mode shapes of spatial lattice structures. The union set, combining the average normalized power spectrum measured at all the test points with an auxiliary normalized power spectrum calculated according to the characteristics of theoretical mode shapes, was defined as the modal identification results. Besides, the judgment criterion was discussed. The improved power spectrum density peak method can avoid the missing of modes and sieve the duplicated frequencies in identification process. A numerical example shows the effectiveness of the method improved. A software was made based on the above theory and has been applied to the monitoring system of the stadium for Shenzhen Universiade.