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Showing 1 to 20 of 54 for “"Acoustic Emissions"”.
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Analysis of soil slopes utilizing acoustic emissions
Includes bibliographical references.
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Acoustic emissions in hydraulic fracturing of Barre granite
The purpose of this work is to observe acoustic emissions (AE) generated by laboratory scale hydraulic fracturing of Barre granite specimens with single or double flaw geometry. The scope of this work covers the experimental setup and subsequent analyses of these acoustic emissions, which in …
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Microprocessor-based system for the detection and characterization of acoustic emissions for materials testing
This document explains the design of the Acoustic Emission Detection and Characterization System (AEDCS). The AEDCS is capable of recording several Acoustic Emmision ( E) characteristics including AE event peak amplitude, duration, frequency, and time of occurrence. The analog and digital circuits …
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Correlation-Based Detection and Classification of Rail Wheel Defects using Air-coupled Ultrasonic Acoustic Emissions
… This thesis presents a passive non-contact acoustic structural health monitoring approach using ultrasonic acoustic emissions (UAE) to detect certain defects on different structures, as well as, classifying the type of the defect on them. The acoustic emission signals used in this study are …
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Using the Finite Discrete Element Method (FDEM) to Correlate Simulated Microfractures to Acoustic Emissions in Brittle Anisotropic Rock
… methods. These include the recording of Acoustic Emissions (AE) during laboratory tests which are elastic vibrations emitted when microcracks form and/or propagate, and numerical simulation using the combined Finite-Discrete Element Method (FDEM). This research applies both laboratory and …
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Passive Tomography to Image Stress Redistribution Prior to Failure on Berea Sandstone and Marcellus Shale for Caprock Integrity
… keeping the fluid within the reservoirs. Passive acoustic emissions monitoring was used to determine how effectively failure locations could be located in three unique tests. Coupled with double difference tomography, the failure of a Berea Sandstone sample and Marcellus Shale sample were …
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Experimental investigation of the flow field during combustion in narrow circular ducts
… during the oscillations. In addition, acoustic emissions from full-tube oscillations were analyzed using velocity data. To my knowledge, the current study is the first attempt to experimentally determine the structure of these oscillatory reactive flows. It was established that the flow …
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Development and Initial Evaluation of an Acoustic Apparatus Used For Testing of Farfield Noise Emitted by a Propeller in a Short Duct
… an apparatus which was used for testing of acoustic emissions by a propeller in a short duct. An apparatus was designed based on a combination of acoustic principles and a desire to be able apply the knowledge gained to a practical application such as an ultralight aircraft in an effort to …
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Acoustic monitoring of hydraulic stimulation in granites
… mechanics the subject of considerable study. Acoustic emissions, or microseisms, contribute greatly to these studies and have been employed on a wide range of topics in rock mechanic studies. At Colorado School of Mines, acoustic emission technology has been employed to monitor stimulation of …
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Cavitation in focused ultrasound
… designed to avoid the formation<br/>of acoustic standing waves, known to have a critical influence<br/>on cavitation behaviour. A new technique of laser-nucleated acous-<br/>tic cavitation is presented, whereby a laser-pulse of energy below the<br/>breakdown threshold for the host …
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Acoustic sensing of renal stone fragmentation in extracorporeal shockwave lithotripsy
… carried out by the author on the exploitation of acoustic emissions detected during extracorporeal shockwave lithotripsy (a non-invasive procedure for the treatment of urinary stones) to develop a new diagnostic system. The work formed part of a research project on lithotripsy undertaken by the …
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Two Studies in Evanescent Wave Propagation (Beam, Acoustic, Gaussian)
… In the first problem, surface motion, excited by acoustic emissions produced by fracture processes at the edge of a buried, penny-shape crack, are investigated. First, wave-front approximations to the emissions generated by the sudden growth of a tensile crack in the unbounded elastic solid are …
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Some rock mechanics problems with application for hydraulic fracturing
… piezoelectric transducers were used to measure acoustic emissions (AE) generated during HF and fault slip.
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Detection of fiber fracture in Unidirectional Fiber Reinforced Composites using an In-Plane Fiber Optic Sensor
… a fiber optic sensor for use in detecting acoustic emissions (AE) in FRP. The results of AE analysis (signal amplitude, frequency spectra, MARSE, and in-plane displacement) caused by simulated fiber fracture experiments and other types of mechanical loading in FRP test coupons are reported. …
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Acoustic emission evaluation of FRP composite specimens in tension and bending
… evaluation of FRP composite structures using Acoustic Emissions was conducted. Seven tension specimens and fifteen bending specimens from three different FRP manufacturers were tested. The hand-laid tension specimens produced at WVU were tested following ASTM D3039. The bending specimens were …
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Acoustic emission signal analysis
An extension of acoustic emission technology was made which permits identification of probable source mechanisms for signals emitted during the failure of metals. This was achieved through the construction of a unique instrument and the development of special computer programs. The instrument …
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Optical fiber detection of ultrasonic vibration and acoustic emission
… the study is to develop a sensor for detecting acoustic emissions (AE) inside composite structures. The basics of wave propagation inside of materials has been presented along with an overview of typical acoustic emission testing. Surface acoustic waves (SAWs) were studied first and a novel, …
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Ultimate Compression After Impact Load Prediction in Graphite/Epoxy Coupons Using Neural Network and Multivariate Statistical Analyses
… an impacted damaged coupon based uniquely on the acoustic emissions it emits at low proof loads. Acoustic emission (AE) data were collected using two 150 kHz resonant transducers which detected and recorded the AE activity given off during compression to failure of thirty-four impacted 24-ply …
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Acoustic Emission Fatigue Crack Monitoring of a Simulated Aircraft Fuselage Structure
… crack grows, it releases energy in the form of acoustic emissions. These emissions are transmitted through the structure in waves, which can be recorded using acoustic emission (AE) transducers. This research employed a pressure vessel constructed out of aluminum and placed under cyclical loads …
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