General Electric Company

John D Young

Kristina H Hedengren

Robert S Gilmore

Frederick C Schoenig, Jr

James D Landry

Donna C Hurley

Robert John Filkins

James Paul Fulton

Thadd Clark Patton

Mark A Joyce

William P Kornrumpf

Robert P Alley

Richard J Charles

Casmir R Trzaskos

Richard O McCary

An exemplary inspection apparatus for inspecting an article comprises a flexible sensor for sensing a characteristic of the article, which sensor conforms to a surface of the article, a finger cover which fits over a finger of a user, and an attachment device for removably attaching the sensor to the finger cover. The apparatus allows the user to traverse the sensor over a large range of smoothly varying concave or convex inspection surfaces, for example, while providing the user with direct control of the sensor.

Finger controlled inspection apparatus

An eddy current surface inspection array probe and method for detecting cracks and flaws in aircraft skin metal immediately surrounding rivets, without requiring rivet removal or manual scanning. The array probe includes a circular array of small sense coils positioned beneath a much larger drive coil encased in ferrite. The sense coils are differentially connected in pairs such that the signals from two sense coils located on opposite sides of the rivet (180.degree. apart) subtract to produce a resultant output signal. During operation, the probe is positioned concentrically over the rivet and data acquired from all sense coil pairs. If no cracks or other defects are present, all sense coil pairs produce a null (zero) signal. If a crack exists, some sense coil pairs (the exact number depending on the crack length, number of sense coils, and sense coil spacing) produce a non-zero signal. The probe and method can be employed to inspect a variety of other structural features which are nominally circularly symmetrical.

Eddy current surface inspection probe for aircraft fastener inspection,

A system and method is provided for aligning a scanning surface of an inspection probe relative to a workpiece surface under inspection. The probe preferably includes at least three alignment eddy current elements, each producing a respective spacing indication electrical signal in accordance with a spacing between each alignment eddy current element and the workpiece. The system further comprises processing means which receives each spacing-indication electrical signal so as to generate data indicative of the relative alignment between the scanning surface of the probe and the workpiece surface. A controller is responsive to the alignment data for aligning the probe such that in operation the scanning surface thereof is substantially parallel relative to the workpiece surface. The probe can include inspection eddy current elements, in which case the alignment and the inspection eddy current elements can be fabricated to form an integral eddy current inspection probe.

System and method for aligning an inspection probe and maintaining

An eddy current probe array is disclosed comprising a plurality of spatially correlated eddy current probe elements sufficiently disposed within a flexible interconnecting structure to collect a discrete plurality of spatially correlated eddy current measurements for nondestructive near surface flaw detection. A plurality of precisely fabricated, substantially identical elements being sufficiently distributed can accommodate inspecting an area of conductor covered by the active width of the array in a single uni-directional scan. The array structure can flexibly conform to accommodate inspection of large, irregular, curved conductive surfaces which cannot be inspected by conventional means.

Flexible eddy current surface measurement array for detecting near

The invention discloses an inspection system for detecting near surface flaws or defects in conductors using nondestructive eddy current testing suitable for industrial application. The system provides a method and apparatus for acquiring real time, synchronized, discrete eddy current measurement signals from a plurality of sufficiently disposed, spatially correlated eddy current probes then processing and formatting said measurement signals automatically over parallel data channels to accommodate digital processing techniques in order to produce on eddy current image. Utilizing digital image processing provides a capability for improving flaw detection limits while simultaneously enhancing image resolution.

Method and apparatus for a multi-channel multi-frequency data

Nuclear fuel cladding tube end plug welds are ultrasonically scanned to develop data indicative of weld thickness, weld penetration, and the existence and size of any included feature, such as pores. A computer analyzes the data to determine critical weld characteristics which are then tested against established quality assurance standards to see if the end plug weld is acceptable, all on an automated production line basis.

Non-destructive dimensional and flaw inspection of thin wall tube

A quality assurance inspection system utilizes a plurality of ultrasonic transducers to probe an elongated tube for both dimensional and structural integrity. The transducers are pulsed in rapid succession, and echo signals are conducted over separate RF channels and through a multiplexor to a lesser number of detector signals channels, each including a discriminator. Inspection windows are opened in these discriminators to permit detection of echo signals and the generation of time mark signals for stopping a plurality of clocks which then register pulse-echo time intervals. These data are computer processed to provide tube dimension and flaw information.

Ultrasonic dimensional and flaw inspection of thin-walled tubular

A phase-difference eddy current imaging system has a bridge circuit including a pair of coils with one or both coils disposed proximate an object that may contain one or more flaws. An oscillator is coupled to the bridge circuit and also to a pair of phase detectors that are coupled to the coils. A differential amplifier is coupled to the phase detectors for providing a comparison signal. A method for eddy current imaging using phase difference detection comprises providing relative movement between an object and at least one of a pair of coils, measuring the phase of the effective reactance in each of the coils, comparing the measured values, and formatting the compared values as a function of spatial position.

Eddy current imaging apparatus and method using phase difference

The present invention is an inspection instrument of the type which reacts to induced eddy currents in a workpiece to be inspected and includes a probe having at least a first probe coil. The instrument further includes a bridge circuit having the first probe coil connected in a first bridge arm. The bridge circuit also has input and output terminals. Connecting cable connects the instrument to a remote signal interpretation unit, and individual buffers connected between each of the output terminals and the cable isolate the capacitive of the cable from the bridge circuit.

Eddy current inspection probe with probe coil resonace reduction

Improved focussing and increased bandwidth is obtained in a single-element ultrasonic transducer for non-destructive evaluation and material characterization applications. The piezoelectric ceramic element has a radius of curvature R.sub.1, and a combination lens and cover layer on its front surface has a radius of curvature R.sub.2 which is less than R.sub.1. The depth of field of the transducer is increased and the bandwidth improved; the total thickness of the lens may be selected to control bandwidth.

Compound focus ultrasonic transducer

A gated peak detector capable of operating at frequencies of the order of 50 Mhz. and with pulse repetition rates of the order of 10,000 pulses per second includes high speed positive and negative peak detectors driving corresponding sample and hold circuits, the outputs of which are combined in a differential amplifier, the output of which is digitized to provide an output digital signal corresponding to the peak-to-peak value of the input waveform. An automatic polarity selector circuit sums the outputs from the sample and hold circuits, compares the sum to a reference voltage, and controls switches connected to the outputs of the sample and hold circuits and to the input of an analog sample and hold circuit which provides an analog output signal corresponding to the larger of the detected peak values.

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Rexford, NY, United States of America

John D Young