Power Spectral Density of Defect Beams Under a Moving Load

Using the vibration signals of damaged beams under the act of a moving load, this article investigates changes in the power spectral density caused by beam damage. Based on the results, the authors have proposed a parameter to monitor a structure’s deteriorating conditions. Cracks were created in beams that changed the stiffness of the structure, and simulations of deterioration were conducted. The features proposed in this article are based on the changing shapes of power spectral density from which deterioration in a damaged beam structure can be detected. The experiment was designed to achieve the simulation that best corresponds to a realistic flow of traffic along bridges. Acceleration sensors installed along the beams received the vibration signals that were used to establish the power spectral density. The results of this article show that for a damaged beam, changes in the shapes of power spectral density are much more prominent than changes in the fundamental frequency value. In other words, when compared to using fundamental frequency changes, using shape changes in power spectral density will increase the likelihood of detecting damage for a variety of beam structures.