Wireless Power Transfer Based Non-Destructive Evaluation of Cracks in Aluminum Material

Sensor design and signal conditioning of eddy-current testing are essential research areas for quantitative testing and evaluation. However, crack quantification relies on the variations of sensing mechanism and signal amplitude, which is susceptible to noise under different interferences, thus providing a limited number of features for evaluation. Therefore, this paper proposes a new concept of wireless power transfer (WPT)-based eddy-current testing and evaluation technique for the first time. The novelty of this technique is the introduction of multiple resonance frequencies as features for crack detection and characterization. Multiple resonances allow the selection of specific features for the best sample and crack characteristics. The experimental results from the artificial slots in two different aluminum samples were analyzed based on resonance points and shape of the response features. The results demonstrate that each crack width along the scan axis is proportional to the width of the two sides around it where eddy-current density is highest. Also, from the crack depth quantification, different feature extractions are compared. The results also showed that the smaller the depth of the crack, the higher the frequency feature and lower the amplitude feature.