Structural Damage Detection in Space Frames Using Modal Strain Energy Method and Genetic Algorithm

Abstract

In this paper, a two-stage damage detection method combining modal strain energy (MSE) method and genetic algorithm (GA) is proposed to identify the location and the extent of multiple damages in space frame structures. The proposed method can detect the damages not only globally in whole structure but also locally in each structural member. In the first stage, a damage index based on the MSE, namely modal strain energy based index (MSEBI), is employed as the criterion to determine the occurrence of the damages among elements in the structure. The MSE is calculated by using the modal analysis obtained from the frame’s finite element model. In the second stage, the GA is utilized to minimize the objective function. The objective function is developed with designed variables correspondingly representing the extent of the damages, which are identified from the first stage. The feasibility of the proposed method is verified by numerical simulation of a real scale space frame structures. Finally, discussions about the proposed method are given.