The Damage Physical Features Extraction Algorithms Based on Denoising FBG Signal in Aluminum Alloy Structures

Fiber Bragg gratings (FBG) sensor has attracted considerable attention for structural health monitoring (SHM) in aerospace aluminum alloy structures in recent years. The experimental FBG signals used to detect flaws contains noise. Therefore, in this paper, an algorithm that combines variational mode decomposition (VMD) with discrete wavelet transform (DWT) was proposed to deal with the signal denoising problem. Then, it is a challenge problem for structural damage detection to extract the features that sensitive to damage and robust to noise from the FBG signal response. This paper presents several damage features extraction algorithms, such as the multi-peaks central wavelength algorithm, full width at half Maximum (FWHM) algorithm, the spectral difference algorithm and the spectral area algorithm. Then, the denoised structure signal can be used to test the damage features extraction algorithm effectiveness and for future damage detection.