Damage detection in beams using vibratory power estimated from the measured accelerations

While there have been several analytical studies to estimate the vibratory power of damaged structures, only a few attempts have been tried to identify the damage for practical implementations. In order to understand the characteristics of the vibratory power in damaged structures, it is necessary to trace the time histories of the instantaneous power in the vicinity of the damage. The spatial distribution of the vibratory power should also be investigated, and a proper damage index is required to diagnose the damage. In this paper, a practicable local damage detection method is proposed using the vibratory power estimated from the accelerations measured on the damaged beam structure. A new damage index is defined based on the proposed damage detection method and is applied to identify the structural damage. Numerical simulation and experiment are carried out on a beam to confirm the validity of the proposed method. In the experiments, the damage considered as an open crack such as slit inflicted on the top surface of the beam. Changes in the vibratory power of the damaged beam are investigated, and the results show that the proposed method identifies successfully the structural damage in the beam.