Efficient Near-Field Radiofrequency Imaging of Impact Damage on CFRP Materials with Learning-Based Compressed Sensing

Abstract

Carbon fiber-reinforced polymer (CFRP) is a widely-used composite material that is vulnerable to impact damage. Light impact damages destroy the inner structure but barely show obvious change on the surface. As a non-contact and high-resolution method to detect subsurface and inner defect, near-field radiofrequency imaging (NRI) suffers from high imaging times. Although some existing works use compressed sensing (CS) for a faster measurement, the corresponding CS reconstruction time remains high. This paper proposes a deep learning-based CS method for fast NRI, this plugin method decreases the measurement time by one order of magnitude without hardware modification and achieves real-time imaging during CS reconstruction. A special 0/1-Bernoulli measurement matrix is designed for sensor scanning firstly, and an interpretable neural network-based CS reconstruction method is proposed. Besides real-time reconstruction, the proposed learning-based reconstruction method can further reduce the required data thus reducing measurement time more than existing CS methods. Under the same imaging quality, experimental results in an NRI system show the proposed method is 20 times faster than traditional raster scan and existing CS reconstruction methods, and the required data is reduced by more than 90% than existing CS reconstruction methods.

A review of FMLs performance test methods and index evaluation

“…Although FMLs has been widely used in engineering companies, but in its production process, due to the process of instability, pores, layer, inclusion, damage, in the use process of defects, also can produce knife marks, scratch, corrosion pit, layered and layered offline damage [84][85][86][87], so the FMLs damage detection and testing is particularly important, also gradually caused the researchers and application of extensive attention. For the nondestructive testing methods of FMLs, they mainly include infrared thermal wave detection, ultrasonic detection, acoustic emission detection and microwave nondestructive testing.…”