DAMAGE QUANTIFICATION OF BEAMS USING FREQUENCY SIGNATURE

Abstract

A rapid method for determining the damage severity sustained by a beam proved to be
challenging due to either limited studies conducted on the subject or alternative methods require highly
sophisticated and costly equipment to perform. In this research, the unique frequency signature emitted by a
beam when excited by an external force was utilized in order to determine the changes in the properties of the
beam. Experiments were performed using a roving accelerometer hammer impact test on a beam with a
grounded 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 software
incorporating Kalman Filter and structural dynamics. Results show that the dominant frequency obtained in both
the Fast Fourier Transform and Power Spectral Density of the acceleration response of the beam decreases as the
damage incurred by the beam increases. The results also show that regardless of the position of the
accelerometer, 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 increase
in damage of the beam corresponds to an increase in the dissipation rate of the beam. The study was able to
achieve its goal of quantifying damage in a beam through the use of frequency signature by identifying the
changes in its dominant frequencies and the damping ratio and dissipation rate.