DAMAGE QUANTIFICATION OF BEAMS USING FREQUENCY SIGNATURE

Abstract

A rapid method for determining the damage severity sustained by a beam proved to bechallenging due to either limited studies conducted on the subject or alternative methods require highlysophisticated and costly equipment to perform. In this research, the unique frequency signature emitted by abeam when excited by an external force was utilized in order to determine the changes in the properties of thebeam. Experiments were performed using a roving accelerometer hammer impact test on a beam with agrounded configuration to test the changes occurring as the controlled damage sustained by the beam increases.The acceleration response of the beam obtained from the experiment is then processed using softwareincorporating Kalman Filter and structural dynamics. Results show that the dominant frequency obtained in boththe Fast Fourier Transform and Power Spectral Density of the acceleration response of the beam decreases as thedamage incurred by the beam increases. The results also show that regardless of the position of theaccelerometer, dominant frequencies tend to converge to a value depending on the damage sustained in the beam.Damping ratio of the beam also decreased as the damage sustained by the beam increased. Inversely, the increasein damage of the beam corresponds to an increase in the dissipation rate of the beam. The study was able toachieve its goal of quantifying damage in a beam through the use of frequency signature by identifying thechanges in its dominant frequencies and the damping ratio and dissipation rate.