Inverse Analysis of Cracked Frame Structures by Genetic Algorithm.

TLDR: In this article, the authors proposed a crack identification method for plane frame structures by relating the eigenfrequencies to the crack location and depth, by combining both the transfer matrix method and the compatibility equation of each segment.

Abstract: A crack in a structural member can change the eigenfrequencies of the undamaged structure. The magnitude of change in the eigenfrequencies is a function of the depth and the location of the crack. By relating the eigenfrequencies to the crack location and depth, we proposed a crack identification method for plane frame structures in present paper. In the FEM vibration analysis for the structures, the crack is simulated by an equivalent rotational spring, connecting the two segments of the beam. The matrix elements containing a crack are derived explicitly by combining both the transfer matrix method and the compatibility equation of each segment. The eigenfrequencies computed by FEM are then applied to studying the inverse problem-identification of crack location from frequency measurements. And the crack identification method is performed by using both the finlte element method and the genetic algorithm. In order to confirm the validity of the proposed method, several frame structures with a crack are analyzed.