Signal processing-based damage detection of steel braced frame subjected to consequent excitations

During the previous decades in civil and structural engineering, methods for detecting structural damage have become a focus of research. The cohesion of the structure is the goal of damage monitoring; thus, damage detection is an essential issue in modern structural design. Many approaches proposed to determine the location and timing of damage. In this paper for diagnosed the structural damage, we used structural responses and applied mathematical transformations to them. To achive this goal, at first, we model a two-story steel frame with converging bracing, the main steel frame subjected to seismic loading in the laboratory of the College of Berkeley, analyzed in the OpenSees. After validating, structural acceleration responses extracted from the OpenSees, when white noise occurs between earthquakes. For investigating structural damage existence, the Fourier transform applied to the acceleration values of the structure and examined them. A decrease in the frequency of the structure is a sign of damage presence. Then took the acceleration of the structure at earthquake time into the MATLAB and analyzed in the wavelet toolbox, and the time of structural damage determined. The acceleration data of each structure and the wavelet transform also used to determine the location of the damage to the structure. A comparison of these results with the laboratory test values shows that the average accuracy of the wavelet transform in detecting the location and time of damage is 99.49% and 96.19% of the laboratory values, respectively.