Eddy current probe and method for determining ply orientation using eddy current and ultrasonic probes
Inventors
Gravagne, Ian • Jack, David A. • Blandford, Benjamin M. • Newton, Matthew • Georgeson, Gary • Chowdhury, Tonoy
Assignees
Publication Number
US-12313592-B2
Publication Date
2025-05-27
Expiration Date
2043-02-24
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Abstract
A system and method for determining fiber orientation within a layered composite using an eddy current probe is discussed. The eddy current probe includes an array of coils that are excited such that an effective pole of the end effector of the probe moves in a ring pattern. The eddy current probe is moved across the surface of a part such that a two-dimensional scan of the part is generated, analogous to a C-scan in ultrasonic testing. The eddy current probe is able to be used to determine the fiber orientation of a layered composite material by scanning at a single point on the material. The eddy current data is able to be fused with data from an ultrasonic transducer to produce a comprehensive view of the part.
Core Innovation
The invention provides a system and method for determining the fiber (ply) orientation within layered composite materials by using an eddy current probe having a two-dimensional matrix of induction coils. The probe operates by activating a linear set of coils aligned along a given axis, and varying the activated set such that the effective excitation axis rotates while the probe remains substantially stationary over a section of the composite. After the effective axis completes at least a full 360° rotation, the probe can then be translated to a new location for further scanning, thereby generating a two-dimensional scan of the part analogous to a C-scan in ultrasonic testing.
A problem addressed by the invention stems from prior art eddy current NDT methods being unable to detect local fiber orientations in composite or anisotropic materials with high spatial resolution, and typically only providing limited information at a single surface location or with arrays aligned in straight lines, which do not allow for the detection of anisotropic conductivity necessary for ply orientation mapping. The invention recognizes that techniques such as physically rotating a probe are imprecise, practical challenges exist with depth or layer-by-layer decomposition, and that fusing eddy current and ultrasonic data for comprehensive analysis is not performed in the prior art methods.
The present invention integrates an ultrasonic transducer with the eddy current probe, permitting collection of ultrasonic scan data such as C-scans at various depths. The probe is positioned near, but does not contact, the material surface. Eddy current data and ultrasonic data can be fused, providing a composite view of the scanned part. Advanced signal processing, such as demodulation into in-phase and quadrature components and normalization methods, enables accurate and repeatable determination of fiber orientation, defect detection, and characterization of anisotropic properties at multiple layers without requiring physical rotation of probe elements.
Claims Coverage
The patent contains three independent claims, each directed to systems and methods for determining ply orientation of composite materials using a specific arrangement of an eddy current probe and an ultrasonic transducer, including associated scanning and signal processing techniques.
Eddy current probe system with two-dimensional matrix of induction coils and ultrasonic transducer
The system comprises an eddy current probe featuring a two-dimensional matrix of induction coils in communication with at least one signal generator and a processor, and an ultrasonic transducer positioned in the center of the matrix. The probe is positioned near but not in contact with the material, and the system uses at least one actuator for moving the probe. The signal generator activates a linear set of coils aligned along a first axis and varies which coils are activated to rotate the axis while the probe stays substantially stationary, with the actuator moving the probe after a full 360° rotation.
Method for determining ply orientation using rotational activation of a set of coils and ultrasonic data acquisition
The method includes providing an eddy current probe with a two-dimensional coil matrix and an ultrasonic transducer at the matrix center, positioning the probe close to the composite surface, activating a linear set of coils along a first axis, and rotating the axis by varying the activated coils while the probe stays substantially stationary. The actuator moves the probe after a full 360° rotation. The method can include performing multiple rotations and averaging, gathering encoder-based location data, ultrasonic scan data (including C-scans), demodulating and filtering signals, and using an alternating current with frequency greater than 10 MHz.
Integrated system for ply orientation mapping and three-dimensional modeling through combined eddy current and ultrasonic scan data
The system features an eddy current probe with a two-dimensional matrix of coils and a central ultrasonic transducer configured to generate C-scan ultrasonic data at different depths and locations. The coil array is driven such that a linear set of coils rotates via electronic activation without physical coil movement. The processor builds a three-dimensional model of the composite using slices derived both from ultrasonic and eddy current scan data.
The inventive features are focused on the design and electronic operation of a two-dimensional matrix eddy current probe in conjunction with an integrated ultrasonic transducer for ply orientation detection, rotational scanning without physical coil movement, and the ability to generate and process comprehensive three-dimensional models combining multi-modal scan data.
Stated Advantages
Determines fiber (ply) orientation of layered composite materials at a single scan location without physical rotation of the probe.
Provides higher resolution and accuracy in detecting ply orientation compared to prior art methods, including ultrasonic-only techniques.
Enables aggregation and mapping of local ply orientation data to generate comprehensive vector fields and three-dimensional representations.
Fuses eddy current data with ultrasonic scan data in real time, yielding a more detailed and informative view of multilayer composites.
Improves sensitivity to surface and subsurface features, defects, or anisotropic conductive properties in composite materials.
Documented Applications
Mapping fiber orientation and ply structure in layered composite materials, such as carbon fiber-reinforced composites.
Inspecting for defects or irregularities, including cracks, delamination, fiber breakage, low bond line thickness, and wrinkles in composite structures.
Detecting lightning strike materials (metal meshes or embedded conductive arrays) within aerospace components.
Detecting foreign conductive objects (e.g., metallic backings) left in composite parts.
Examining and measuring the thickness or uniformity of conductive and non-conductive surface coatings, paint, sealants, or functional coatings.
Inspecting printed circuitry elements and surface patterns on materials, including additively manufactured items.
Analyzing layered materials with alternating conductivity (e.g., plastic-metal, composite-metal joints, or hybrid structures).
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