Structural damage identification based on the method of generalized uniform load surface curvature

Abstract

In view of the fact that the lower-order structural modes can be obtained easily in practice and the structural parameters before damage are unknown, the generalized uniform load surface curvature method based on least squares polynomial fitting is proposed to detect structural damage. First of all, the modal flexibility curvature method and the uniform load surface curvature method derived from the modal flexibility curvature are analyzed theoretically, and then, combining with the concept of generalized modal flexibility matrix, the generalized uniform load surface curvature method is obtained, and the generalized uniform load surface curvature method based on least squares polynomial fitting is put forward finally. Second, taking the numerical simulation of a T-beam fixedly supported at both ends as an example, the damage identification effect of the four methods mentioned above is calculated and compared. The results show that the generalized uniform load surface curvature method based on least squares polynomial fitting needs only lower-order modal parameters after the structural damage, can well identify not only the damage location but also the damage degree of the single damage or the multiple damage, and presents small truncation errors. Compared to the other three methods, it has certain advantages. Finally, the damage of a T-shaped simply supported beam is identified by using the proposed method, which verifies the effectiveness of the method, and hence, this method has important practical application value.