Eddy Current Imaging of Fiber Textures in CFRP Composite Based on Spatial Frequency Domain De-aliasing Method

doi:10.3901/JME.2022.04.014

Abstract

Abstract: The spatial resolution is a key indicator of image quality and is of great importance in the application of eddy current imaging technology. Concerning the aliasing problems including coarse and fuzzy fiber textures in eddy current imaging of carbon fiber reinforced polymer(CFRP) composites, the spatial-frequency domain image enhancement method is studied to significantly improve the detection accuracy of meso-structures and defects such as the fiber direction, in-plane waviness, wrinkles, and gaps in CFRP laminates. In this paper, the mesoscopic electromagnetic simulation model of CFRP laminate is firstly established to reveal the eddy current imaging mechanism and the aliasing law of periodic structure signals. Then the point spread function (PSF) of the eddy current probe is studied and estimated, and the signal feature extraction technology is used to evaluate the spatial resolution of the T-R probes with different sizes. Finally, a texture thinning and focusing method based on PSF and fast Fourier transform (FFT) de-convolution is developed to realize high-precision imaging of fiber direction and layup defects in CFRP laminates, and to achieve the purpose of reflecting the true shape of defects in composite structures.

Key words: eddy current testing, CFRP, texture imaging, point spread function, deconvolution

CLC Number:

TG156

CHENG Jun, YOU Yong, WANG Buyun, XU Dezhang, YU Cheng, YANG Jiquan. Eddy Current Imaging of Fiber Textures in CFRP Composite Based on Spatial Frequency Domain De-aliasing Method[J]. Journal of Mechanical Engineering, 2022, 58(4): 14-21.

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