Improved ultrasonic detection using the analytic signal magnitude

Gammell, Paul M.

doi:10.1016/0041-624x(81)90111-6

Cited by 94 publications

(29 citation statements)

References 3 publications

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“…This results in a value (η) proportional to the ultrasonic energy transmitted through the crimp [5]. These values are plotted against the load at failure for each specimen.…”

Section: Discussionmentioning

confidence: 99%

A Method for the Verification of Wire Crimp Compression Using Ultrasonic Inspection

Cramer

Perey

Yost

2010

Research in Nondestructive Evaluation

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The development of a new ultrasonic measurement technique to assess quantitatively wire crimp terminations is discussed. The amplitude change of a compressional ultrasonic wave propagating at right angles to the wire axis and through the junction of a crimp termination is shown to correlate with the results of a destructive pull test, which is a standard for assessing crimp wire junction quality. To demonstrate the technique, the case of incomplete compression of crimped connections is ultrasonically tested, and the results are correlated with pull tests. Results show that the nondestructive ultrasonic measurement technique consistently predicts good crimps when the ultrasonic transmission is above a certain threshold amplitude level. A quantitative measure of the quality of the crimped connection based on the ultrasonic energy transmitted is shown to respond accurately to crimp quality. A wave propagation model, solved by finite element analysis, describes the compressional ultrasonic wave propagation through the junction during the crimping process. This model is in agreement within 6% of the ultrasonic measurements. A prototype instrument for applying this technique while wire crimps are installed is also presented. The instrument is based on a two-jaw type crimp tool suitable for butt-splice type connections. A comparison of the results of two different instruments is presented and shows reproducibility between instruments within a 95% confidence bound.

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“…This results in a value (η) proportional to the ultrasonic energy transmitted through the crimp [5]. These values are plotted against the load at failure for each specimen.…”

Section: Discussionmentioning

confidence: 99%

A Method for the Verification of Wire Crimp Compression Using Ultrasonic Inspection

Cramer

Perey

Yost

2010

Research in Nondestructive Evaluation

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“…This impulse response was identified previously by Gammell as the analytic signal in the context of ultrasound [6,7]. The current approach in obtaining the microwave pulse reflection characteristics follows his ultrasonic approach.…”

Section: Impulse Responsementioning

confidence: 99%

Air-Gap Detection in Dielectric Materials by a Step-Frequency Microwave Technique

Liu

1996

Review of Progress in Quantitative Nondestructive Evaluation

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“…The analytic signal of a waveform has the waveform as its real part and its Hilbert transform as the imaginary part. The magnitude of the analytic signal represents a more accurate measure of the signal envelope than the conventional rectification and smoothing [2].…”

Section: Signal Processingmentioning

confidence: 99%

Practical application of state-of-the-art NDE techniques: evaluation of graphite-epoxy composite wing covers

1994

NDT & E International

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The X-29 experimental aircraft, based at the NASA Dryden Flight Research Facility, Edwards Air Force Base, California, represents a demonstrator for several state-of-the-art aerospace technologies. The most obvious of these is the forward-swept wing configuration, made possible in this high-performance aircraft by the use of graphite fiber-reinforced epoxy composite laminate wing surfaces. During a routine inspection of the aircraft, a delamination was found in the wing on the right underside of the airplane. A NASA review board investigated the damage and recommended to repair the delamination and to closely monitor its integrity during the post-repair period. The local strain on the surface of the repaired part was measured with strain gages monitored in real time during subsequent flights and the area was periodically inspected nondestructively in a reproducible manner to test for failure of the repair or growth of the delamination. The Materials Characterization Instrumentation Section of the NASA Langley Research Center was called upon to acquire quantitative ultrasonic NDE data from the repaired delamination and to analyze it using the advanced techniques available at that facility. These measurements were in addition to more subjective conventional ultrasonic pulse-echo inspections. THE DELAMINATIONThe delamination occurred on the inboard leading edge of the lower right wing cover, on a tab containing nut plates fastened by rivets for mounting the adjacent boot paneL Fig. 1 shows a sketch of the affected composite part. The composite is 48 plies thick at the edge, with the delamination occurring approximately 4 plies from the upper (interior to the wing) surface. The composite part is separated from a structural titanium spar by a layer of silicon-loaded epoxy, referred to as liquid shim, to reduce vibrations.The delamination was repaired according to the following procedure. First, the cured liquid shim material was removed from between the composite and titanium spar behind the delamination. The crack was pried open slightly to aid in the injection of a liquid epoxy, Epon 934, into the crack. This epoxy is similar, but not identical, to the matrix material of the composite. A wedge was inserted between the composite and the titanium spar to close the crack during cure of the epoxy. After cure, the wedge was removed and the gap between composite and titanium was filled with liquid shim.Conventional pulse-echo ultrasonic inspection was performed, and the 995

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Improved ultrasonic detection using the analytic signal magnitude

Cited by 94 publications

References 3 publications

A Method for the Verification of Wire Crimp Compression Using Ultrasonic Inspection

A Method for the Verification of Wire Crimp Compression Using Ultrasonic Inspection

Air-Gap Detection in Dielectric Materials by a Step-Frequency Microwave Technique

Practical application of state-of-the-art NDE techniques: evaluation of graphite-epoxy composite wing covers

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