基于主元分析和频响函数的网架结构损伤识别方法

A METHOD OF TRUSS STRUCTURAL DAMAGE IDENTIFICATION BASED ON PRINCIPAL COMPONENT ANALYSIS AND FREQUENCY RESPONSE FUNCTION

提出了以频响函数作为损伤识别的基本参变量,利用主元分析和多元控制图来识别网架结构损伤的方法。首先利用网架动测得到的频响函数数据建立原始资料矩阵,运用主元分析方法,对原始资料阵进行降维处理,然后利用携带原始数据信息最多的前几阶主元,在低维空间中对数据信息特征进行分析、提取。由前几阶主元作出多元控制图,通过分离异常数据,来识别网架结构的损伤。为了验证该方法的可靠性,试验完成了足尺网架在单杆和双杆等4种不同损伤情况下动测试验。结果显示,提出的方法是可行的、可靠的,对在噪声环境下和具有弱非线性网架的损伤识别有良好的适应性。该方法不需要模态参数,避免了模态拟合中的误差,识别过程简捷,识别结果可靠。

A method of truss damage identification is proposed based on the principal component analysis and multivariate control chart using frequency response functions as basic variables. Original data matrix is formed using frequency response function obtained from truss dynamic test. With principal component analysis, the variable space dimensions of original data can be reduced. Then the characteristics of original data can be analyzed and extracted from lower dimension space using first several principal components which contain the most original data information. The truss damages can be identified by separating the singular data in the control chart, which is formed using first several order principal components. In order to validate the reliability of the proposed method, a full-size truss was tested in four kinds of damage cases concerning single and double element damages. The result shows that the proposed method is reliable and has a good adaptability for slight non-linearity truss under the noise environment. Since the proposed method does not need modal parameters and avoids the errors of modal extraction, it is straightforward and accurate for truss damage identification.