改进的特征值灵敏度在结构损伤识别中的应用

Structure Damage Detection Based on Improved Eigen Value Sensitivity

传统的特征值灵敏度分析中忽略了振型变化的影响,导致特征值灵敏度难以准确地识别出结构损伤。为提高特征值灵敏度的准确性,利用未损伤结构的振型线性表示损伤情况下结构振型的变化,进而改进了特征值灵敏度的理论分析方法。在不同的损伤工况下,计算数值模型改进前后的特征值灵敏度,验证表明改进后的特征值灵敏度具有更高的精度。以孔洞直径和位置均未知的实际结构为研究对象,利用改进后灵敏度方法准确识别了结构损伤的位置和程度,与结构的孔洞直径和位置实测值相吻合,表明了改进后灵敏度方法具有准确实用性,从而弥补了传统特征值灵敏度法在结构损伤识别中的缺陷。

As structural damage may affect performance and even lead to structural failure,the identification of structural damage is crucial.Testing mode parameters such as mode eigen values,natural frequencies and mode shapes is simple and convenient.It makes more sense for the eigen value to be objective for damage detection due to its higher sensitivity for structural damage compared with natural frequencies and mode shapes.However,it was difficult to use the traditional eigen value sensitivity method to identify structural damage accurately,because it was easy to ignore the change of mode shape.In order to improve its accuracy,the change of structure mode shape could be substituted with the linear combination of undamaged structure mode shapes,thus improving the eigen value sensitivity analysis method.The traditional and improved sensitivity was calculated under various damage conditions,and the comparison showed higher accuracy.The improved eigen value sensitivity method was applied to a real structure with holes of unknown size and location.The identified results showed that the accurate damage level and location were identified,thus validating the accuracy and practicability of this improved sensitivity method.