An Efficient Phenomenological Inversion Method for Reconstruction of Crack Depth Profile in a Metal From ACFM Probe Output Signals

The paper proposes an efficient phenomenological inversion method to determine the depth profile of a surface-breaking crack in metal from output signal alternating current field measurement (ACFM) probe. proposed utilizes conjugate gradient algorithm minimize objective function, representing difference between probe predicted and actual signals iterative manner. function is derived explicitly terms variables by considering polynomial for distribution direction applying appropriate Greens functions. This approach enhances accuracy computational efficiency process, regardless choice initial or presence noise system. validity are demonstrated comparing reconstructed profiles several simulated machine-made cracks with their data, those obtained using conventional based on stochastic optimization scheme along fast pseudoanalytic ACFM simulator.