环境激励下结构模态参数识别的改进ITD法

发布时间：2018-05-03 17:50

本文选题：环境激励 + 模态参数识别　；参考：《振动与冲击》2014年01期

【摘要】：结合随机子空间法(SSI)提出了环境激励下结构模态参数识别的改进ITD法。随机子空间法的识别精度高,其中数据的协方差计算可以保留原始数据中的所有信息,同时去除了噪声,得到的Toeplitz矩阵中的数据可以作为ITD法的输入数据,这样ITD法不再需要采用随机减量法或者自然激励技术(NExT法)进行前处理,从而避免了这两种前处理方法的不准确性带来的误差。通过环境振动下四层钢框架模型试验的位移响应,对提出的改进ITD法进行了验证。与ITD法相比,改进的ITD法明显提高了对频率和阻尼比等结构模态参数的识别精度,表明改进ITD法可应用于结构的模态参数识别;与SSI法相比,改进ITD法精度没有降低,同时缩短了计算时间,这将为该方法应用到结构的实时监测提供了可能。
[Abstract]:Combined with random subspace method (SSI), an improved ITD method for structural modal parameter identification under ambient excitation is proposed. The random subspace method has high recognition accuracy, in which the covariance calculation of the data can retain all the information in the original data, and at the same time the noise is removed. The obtained data in the Toeplitz matrix can be used as the input data of the ITD method. In this way, the ITD method does not need to adopt the random reduction method or the natural excitation technique (NExT method) to carry on the pre-processing, thus avoids the error caused by the inaccuracy of these two pre-processing methods. The improved ITD method is verified by the displacement response of the four-story steel frame model test under ambient vibration. Compared with the ITD method, the improved ITD method obviously improves the accuracy of structural modal parameters, such as frequency and damping ratio, which indicates that the improved ITD method can be used to identify the modal parameters of the structure, and the improved ITD method has no lower precision than the SSI method. At the same time, the computation time is shortened, which makes it possible for the method to be applied to the real time monitoring of the structure.
【作者单位】：重庆大学山地城镇建设与新技术教育部重点实验室;重庆大学土木工程学院;
【基金】：重庆市建设科技计划项目(2012-2-49,2011-2-86)
【分类号】：TU317

【参考文献】