Abstract: In an approach to detection of grinding burns on high strength steel through chrome plating comprising: a frequency generator device; a scanning device; one or more computer processors; one or more non-transitory computer readable storage media; and program instructions stored on the one or more non-transitory computer readable storage media for execution by at least one of the one or more computer processors, the stored program instructions including instructions to: calibrate the system; inject a low frequency signal into a Device Under Test (DUT); scan the DUT and receive a resulting eddy current (EC) signal response; extract one or more real components and one or more imaginary components of the resulting EC signal response; and perform a phase rotation on the one or more orthogonal components of the resulting EC signal response to highlight one or more effects of interest.

Abstract: A method of testing the residual stress around a cold-worked hole in a test material. The test uses two identical eddy current coil pairs, each pair having a driving coil and a pickup coil. One coil pair is placed into the cold-worked hole. The other coil pair is placed into a non-cold worked hole in a reference material. When the coils are activated, and with a properly chosen phase difference between the excitation signal and the output signal, the in-phase component of the output voltage signal can be correlated to residual stress around the cold-worked hole.

Abstract: A method of testing the residual stress around a cold-worked hole in a test material. The test uses two identical eddy current coil pairs, each pair having a driving coil and a pickup coil. One coil pair is placed into the cold-worked hole. The other coil pair is placed into a non-cold worked hole in a reference material. When the coils are activated, and with a properly chosen phase difference between the excitation signal and the output signal, the in-phase component of the output voltage signal can be correlated to residual stress around the cold-worked hole.

Abstract: Products are disclosed for measuring electromagnetic fields. One embodiment has at least two coplanar magneto-resistive sensors. Each magneto-resistive sensor has a sensitive axis in the plane of the at least two coplanar magneto-resistive sensors. The at least two magneto-resistive sensors may be orthogonally arranged about a central point to measure orthogonal components of electromagnetic fields.

Abstract: The present invention is directed to configurations of eddy current probes and methods for using these probes to detect cracks initiating at the edge of holes in single-layered or multi-layered metallic structures. The new devices and methods are suitable to detect buried cracks around fastener holes located in layers of multi-layered structures, for example in airplane wing splices, containing fasteners disposed in rows. The probes include excitations coils and one or more magnetic sensors. The magnetic sensors can be arranged in absolute, differential or array configurations. The probe is scanned linearly along the fastener row. The invention also contains an apparatus or system for monitoring cracks around holes, including signal processing circuits, driving circuits, data acquisition and display, and scanning systems.

Abstract: Products are disclosed for measuring electromagnetic fields. One embodiment has at least two coplanar magneto-resestive sensors. Each magneto-resistive sensor has a sensitive axis in the plane of the at least two coplanar magneto-resistive sensors. The at least two magneto-resistive sensors may be orthogonally arranged about a central point to measure orthogonal components of electromagnetic fields.

Abstract: A giant magnetoresistive (GMR) based eddy current sensor including a giant magnetoresistive sensor integrated on a silicon chip with a signal conditioning circuit and a circular coil.