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Quantifying the Relative Thickness of Conductive Ferromagnetic Materials Using Detector Coil-Based Pulsed Eddy Current Sensors
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Modelling Eddy Current Testing of Gaps in Carbon Fibre Structures Based on Spline Approximation
Till Schulze1,2, Maren Rake1, Dirk Hofmann1
1Fraunhofer Institute for Ceramic Technologies and Systems IKTS, 01109 Dresden, Germany.
Sensors (Basel, Switzerland)
|February 13, 2026
Summary
This study introduces a new finite element modeling method for carbon fibre composites, improving defect detection with eddy current testing. The validated model accurately simulates electromagnetic properties and identifies gaps, enhancing manufacturing quality control.
Area of Science:
- Materials Science
- Non-destructive Testing
- Computational Electromagnetics
Background:
- Defects in carbon fibre-reinforced composites (CFRPs) like gaps and delamination compromise structural integrity.
- Eddy current testing (ECT) is crucial for early defect detection in CFRP manufacturing.
- Validated electromagnetic modeling is essential for advancing ECT sensor development and signal interpretation.
Purpose of the Study:
- To develop a novel finite element modeling (FEM) approach for CFRPs that accounts for fibre heterogeneity.
- To improve the accuracy of ECT simulations for defect characterization.
- To validate the proposed FEM approach against experimental ECT data.
Main Methods:
- A finite element modeling approach using spline approximation to represent fibre heterogeneity.
- Adaptive mesh refinement to minimize FEM solution errors.
- Modeling inter-laminar current paths via four-terminal resistance measurements.
- Simulating defects like gaps by adjusting spline approximations.
Main Results:
- The proposed FEM approach successfully models the electromagnetic properties of CFRP structures.
- Simulations accurately predict eddy current signals for various defect sizes.
- Virtual scans from the model show strong agreement with experimental ECT scans of real and artificially gapped CFRP samples.
Conclusions:
- The novel FEM approach provides a validated method for simulating eddy current testing in CFRPs.
- This technique enhances the understanding of ECT signals and aids in the development of new sensors.
- The model's ability to account for fibre heterogeneity and inter-laminar currents improves defect detection accuracy in composite manufacturing.
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