A Novel Magnetic Flux-Convergence Semi-Ellipsoidal Eddy Current Probe for Defect Detection

To enhance detection sensitivity and improve defect detection capabilities, existing probe improvements typically involve altering the coil’s geometric structure or adding magnetic cores or shielding to pancake-shaped excitation coils. However, these approaches lack an overall optimization design of the probe structure. To address this gap, this study proposes a novel magnetic flux-convergence eddy current probe featuring a semi-ellipsoidal excitation coil, a super-permalloy core attached to the excitation coil, and a single detection coil. Initially, a finite element model (FEM) of the semi-ellipsoidal excitation coil was developed and compared with a pancake-shaped coil to verify its magnetic flux convergence effect. To further analyze the influence of different core tip structures on the probe’s defect detection performance, cores with parabolic, wedge-shaped, and conical tip structures were fabricated. Subsequently, response surface methodology was employed to optimize the probe parameters, thereby yielding the most optimal geometric configuration for practical application. Finally, detection experiments were conducted on six artificial defects with varying depths and widths on an aluminum plate. The proposed probes demonstrated remarkable efficacy in identifying defects, thereby exemplifying exceptional detection performance. Among them, the probe with the conical tip core structure yielded the best results. These findings indicate that this novel probe exhibits considerable potential for utilization in defect detection applications.