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Electromagnetic Modeling and Inverse Methods for Eddy Current Characterization of Carbon Fiber Composites

Measurement of the fiber orientation and areal weight along with discontinuity detection in a carbon fiber composite are crucial in under-standing the load carrying capability of the structure. Manufacturing conditions including resin flow and molding pressures can alter fiber orientation, and hand or robotic fiber layup processes can be difficult to certify. Verification of the as-designed fiber layup thus becomes necessary to ensure optimal performance of the structure. In this work, the application of eddy current techniques for analysis of carbon fiber composites is presented. A proposed transmit-receive eddy current probe is modeled, and its response to an anisotropic multi-layer conductor simulated and compared to experimental data. The inductively coupled single-sided measurement enables composite characterization through the thickness of the part. The capabilities of eddy current analysis for advanced composites will be shown, and an inversion algorithm to enable determination of layup and impact damage across a composite structure will be presented. The fast and cost-effective technique can be applied as a spot check or as a surface map of the composite properties across the structure.


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