Topic
Acoustic emission
About: Acoustic emission is a research topic. Over the lifetime, 16293 publications have been published within this topic receiving 211456 citations.
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TL;DR: In this paper, the authors revisited acoustic emission (AE) data from an in situ rock fracture experiment conducted at the Underground Research Laboratory (URL) in Manitoba, Canada, which involved the mechanical excavation of a cylindrical tunnel.
Abstract: In this paper, we revisit acoustic emission (AE) data from an in situ rock fracture experiment conducted at the Underground Research Laboratory (URL) in Manitoba, Canada. The Mine-By experiment, a large-scale excavation response test, was undertaken at a depth of 420 m and involved the mechanical excavation of a cylindrical tunnel. During the experiment a small array of 16 Panametrics V103 AE sensors enclosed a 0.7 m × 0.7 m × 1.1 m rectangular prism of Lac du Bonnet granite located in the tunnel wall. The V103 sensors were later calibrated in the laboratory, and a source parameter analysis was undertaken using a spectral fitting method. Corner frequency and moment magnitude were found to be inside the ranges 250 kHz
76 citations
TL;DR: In this paper, a calibrated four-channel elastic wave recording system was used to detect and characterise acoustic emission events associated with the growth of a fatigue crack in a compact tension specimen of 7010 aluminium alloy.
Abstract: A calibrated four-channel elastic wave recording system has been used to detect and characterise acoustic emission events associated with the growth of a fatigue crack in a compact tension specimen of 7010 aluminium alloy. The transducers sampled the elastic wave field in four independent directions in a plane perpendicular to the crack. The 2-D force dipole representation of each event, assumed to be a point source, was deduced by inversion of the Green's tensor. Each emission event was then characterised in terms of source type (e.g. microfracture, slip), orientation relative to fatigue crack and size (e.g. crack volume).
76 citations
TL;DR: In this article, a two-dimensional detection of ultrasonic waves is based on pressure-induced changes of optical reflectance at a glass-liquid interface, imaged with a time-gated video camera.
Abstract: Two-dimensional detection of ultrasonic waves is based on pressure-induced changes of optical reflectance at a glass–liquid interface, imaged with a time-gated video camera. The method is used to record optoacoustic waves generated after irradiation of optically absorbing targets with 6 ns long laser pulses. Measurements of absolute pressure values with high temporal and spatial resolution (in the range of 10 ns and 10 μm, respectively) is demonstrated. The sensitivity is varied between 0.19% and 0.81% gray level modulation per bar. The detector plane is optically transparent, making it possible to irradiate the sample through the detector without disturbing the acoustic measurement. Two-dimensional recording of ultrasonic waves is ideally suited for the analysis of acoustic emission from small sources and for optoacoustic imaging of optical absorption differences in an opaque material.
76 citations
01 Jan 1978
TL;DR: In this paper, the displacement of an arbitrary point on an infinite plate due to a point source force function is computed using a Fourier inversion technique, which yields exact formulas similar to those developed for seismological "ray" theories.
Abstract: Acoustic Emission (AE) signals are notorious for their complexity and irreproducibility. Because AE source characteristics are virtually unknown and because the detected AE signals are colored by the propagation media, the sensor response and the instrumentation set tings, interpretations of test results such as spectral analysis or correlation studies are mostly qualitative and sometimes controversial; theories either are empirically derived or cannot be verified by experiments . In this paper, we sketch an approach to the AE signal analysis problem. We first report the development of a theory which allows the computation of the displacement as a function of time at an arbitrary ·point on an infinite plate due to an arbitrary point source force function . The theory is based on a new Fourier inversion technique which yields exact formulas similar to those developed for seismological "ray" theories. We then report experimental results obtained on a 2. 52 em thick aluminum plate using a reproducible step function stress release pulse as a simulated AE signal and a wide band displacement capacitive transducer as a sensor. The measurements are in quantitative agreement with the predictions of theory. We also discuss applications wherein the simulated signal, capacitive transducer and plate theory are used for AE source signature analysis, and sensor calibration problems.
75 citations
TL;DR: In this paper, three types of woven carbon/carbon composites having differentiations during the manufacturing procedure, which influences their fibre/matrix interface were tested under tensile loading in a load-unload-reload configuration, with online acoustic emission monitoring.
75 citations