Finite Element Modelling of a Reflection Differential Split-D Eddy Current Probe Scanning Surface Notches

Area of Science:

• Non-destructive testing
• Electromagnetism
• Computational modeling

Background:

• Differential eddy current probes are vital for detecting surface cracks in conductive materials.
• Developing analytical models for these probes presents significant challenges.
• Numerical modeling, specifically Finite Element Modeling (FEM), offers a viable alternative.

Purpose of the Study:

• To simulate the interaction between a differential split-D probe and electrical discharge machined (EDM) notches using FEM.
• To validate the accuracy of FEM by comparing simulation results with experimental data.
• To investigate key parameters influencing reliable FEM simulations for eddy current probes.

Main Methods:

• Employed 3D Finite Element Modeling (FEM) to simulate a reflection differential split-D probe.
• Modeled a multi-turn cylindrical absolute coil to refine FEM parameter setup.
• Validated simulation of the absolute coil against existing experimental impedance data for aluminum notches.
• Investigated mesh size, distribution, air domain extent, and air conductivity for FEM accuracy.

Main Results:

• FEM simulation results for the differential probe closely matched experimental impedance measurements.
• The study successfully simulated probe impedance variations across EDM notches of varying depths in aluminum.
• FEM parameter investigations provided insights into achieving reliable simulation outcomes.

Conclusions:

• FEM is a reliable tool for simulating differential eddy current probes and their interaction with surface defects.
• The validated FEM approach can accurately predict probe impedance variations, aiding in non-destructive evaluation.
• This study establishes a robust methodology for the FEM of eddy current probes for crack detection.