Demonstration of model-based inversion of electromagnetic signals for crack characterization

Abstract

The objective of this work is to demonstrate model-based inversion techniques to characterize the length, depth, width, and orientation of surface-breaking cracks using eddy current (EC) NDE. The paper presents experimental testing to acquire high fidelity automated eddy current data, enhancements made in VIC-3D® to improve both speed and accuracy, benchmark studies demonstrating model accuracy, improved data registration and reduction methods, and surrogate models and model calibration schemes to ensure the fastest and highest quality models are used for inversion. Initial inversion results indicate the potential to accurately size cracks and EDM notches over a wide range of flaw characteristics and probe orientations. Insight into EC variability for POD crack sets is presented using inversion results for crack length and depth.