Damage detection and localization on structural connections using vibration-based damage identification methods

Damage detection based upon changes in vibration characteristics is one of the few methods that can monitor the structure on a global basis. The basic idea of this method is that any changes in the physical properties of the structure (mass, stiffness and boundary conditions) will in turn cause changes in its modal characteristics (resonant frequency, modal damping and mode shapes). In this paper different damage detection methods, based on change in frequency and in mode shapes, have been summarized and applied using experimental and numerical data from steel beam before and after releasing some supporting bolts. Two multi-layer piezoelectric actuators were used for excitation; the advantages of using this technique of excitation are explained. Effectiveness in detecting and localizing the damage is compared for the different damage detection methods.