Damage identification of steel structures based on changes in the curvature of power spectral density

Abstract

Damage detection as determined by changes in the dynamic properties or response of structures is a subject that has received considerable attention in literature in recent years. The idea is that the occurrence of damage or loss of integrity in a structural system leads to a changed response to dynamic forces caused by changes in the dynamic properties of the structure (eigenfrequencies, modal damping ratios, mode shapes and/or transfer functions). Based on changes in Power Spectral Density (PSD), this paper proposes a damage identification technique that detects damage and its location. The method is applied to the experimental data extracted from a steel bridge model and a bookshelf structure after inducing some defects to their members. Several damage scenarios were introduced to the members of the bridge model and the bookshelf structure. The method detected the damage and determined its damage location accurately in both structures. In addition, the results illustrate that changes in the PSD curvature can be a useful tool for continuous monitoring of structural integrity using ambient vibration data. Furthermore, changes in the PSD curvature do not require a very fine grid of measurements to detect and locate damage effectively. The effectiveness of the applied technique is studied, at the same time the potential difficulties associated with the application of the proposed method are discussed.