Ultrasonic Excitation – Fiber Bragg Grating Sensing Technique for Damage Identification

Abstract

Nondestructive testing plays an important role in on-line equipment inspection. Traditional nondestructive testing methods have been widely utilized for this. Ultrasonic excitation-fiber Bragg grating sensing technique is based on well-developed optical fiber grating technology, which has a good prospect of damage detection for mechanical equipments. However the corresponding research is still at the starting stage and further research work is necessary. The main contribution pursued in this investigation is to establish a detection system based on fiber Bragg grating sensing under ultrasonic excitation and predict the damage position through time delay on the plate structure. Differencing from the conventional approaches, a new way of damage detection utilizes fiber Bragg grating sensors and a position algorithm by two-dimensional method is derived. Moreover, wavelet transform is adopted in the subsequent signal processing. Finally, a platform for experiment is built to verify the theoretical analysis of the sensing characterization of the fiber Bragg grating sensor in ultrasonic excitation. Experiment results show that the wavelet transform is effective for signal denoising and our localization algorithm is feasible.