Global ETD Search
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Showing 1 to 20 of 81 for “"Acoustic emission (AE)"”.
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Modeling of Acoustic Emission Failure Mechanism Data from a Unidirectional Fiberglass/Epoxy Tensile Test Specimen
<p>The purpose of this work was to model the acoustic emission (AE) flaw growth data that resulted from the tensile test of a unidirectional fiberglass/epoxy specimen. The data collected and stored during the test were the six standard AE quantification parameters for each event. A classification …
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Long Term Health Monitoring of Anthony Wayne Bridge Main Cable with Acoustic Emission Technique
The acoustic emission (AE) technique, based on the sudden release of energy within a material generating transient elastic wave propagation, is widely used as a non-destructive technique (NDT). AE events generate a spectrum of stress waves starting at 0 Hz, and typically falling off at several MHz …
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Defect and fracture detection using acoustic emission monitoring
… investigates the flaw detection capabilities of Acoustic Emission (AE) technology applied to metal alloys and composite materials. The thesis explores the background to AE and how it is applied to flaw detection and fracture characterisation. In preliminary tests, a steel pressure vessel and a …
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Filtering of Acoustic Emission Data Through Principal Frequency Component Extraction
<p>Rapid editing of acoustic emission (AE) data is required in order to make real-time acoustic emission flaw growth systems a viable testing method for materials and setups that contain noisy signals. It was hypothesized that extracting major frequency components from the acoustic emission signal …
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Isolating Failure Mechanisms in a Fiberglass/Epoxy Tensile Test Specimen Using Acoustic Emission Signal Parameters
<p>This study used acoustic emission (AE) signal parameters to isolate the failure mechanisms in a 0° unidirectional, fiberglass/epoxy tensile test specimen. Since several failure mechanisms were known to be present, the lack of any distinctly identifiable bands in the original amplitude …
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Composite Structure Ultimate Strength Prediction from Acoustic Emission Amplitude Data
<p>The acoustic emission (AE) given off by a structure as it is stressed provides a passive means to characterize flaw growth activity in complex structures. This thesis demonstrates how the qualitative analysis of AE data can be refined to provide a quantitative tool for predicting the ultimate …
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The Propagation of Stress Corrosion Cracks in Alpha-Brasses
… associated with the detection of a discrete acoustic emission (AE). By periodically increasing the deflection during these studies, crack front markings were produced on the resulting fracture surfaces and these showed that the crack front at the free surface did not lag behind the overall …
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Prediction of Fatigue Life in 7075-T6 Aluminum from Neural Network Analysis of Acoustic Emission Data
<p>Through the use of an acoustic emission (AE) data acquisition system, a Kohonen self-organizing map, and a back-propagation neural network, AE data from 7075-T6 aluminum specimens were used to classify failure mechanisms and predict the number of fatigue cycles to failure. AE waveforms were …
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Quantitative Analysis of Acoustic Emission From Rock Fracture Experiments
… aims to advance the methods of quantitative acoustic emission (AE) analysis by calibrating sensors, characterizing sources, and applying the results to solve engi- neering problems. In the first part of this thesis, we built a calibration apparatus and successfully calibrated two commercial …
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Stability and quench protection of high-temperature superconductors
… have investigated the first two issues as well acoustic emission (AE) technique as a possible mean for an early detection of a quench. For most of the experimental work reported here, we used "pancake" coils wound with coated YBCO conductor, the HTS of choice by those currently developing …
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Neural Network Burst Pressure Prediction in Composite Overwrapped Pressure Vessels from Acoustic Emission Data
<p>Composites have grown in importance in the aerospace industry where high specific strength is a priority. Weight reduction in space vehicles is critical because of the exorbitant cost associated with placing objects into space. Major weight savings have been obtained by switching from all metal …
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Neural Network Fatigue Life Prediction in 7075-T6 Aluminum from Acoustic Emission Data
<p>The objective of this research was to classify acoustic emission (AE) -data associated with fatigue cracks in aluminum fatigue specimens and to use early cycle life AE data to predict failure in such members. An AE data acquisition system coupled with a Kohonen self organizing map and a back …
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Custom-Engineered and Additively Manufactured Components for Strengthening Steel Bridges
… linking changes in mechanical properties to acoustic emission (AE) response and damage behavior. The second contribution is the development of a smartphone-assisted photogrammetry framework for quantifying corrosion-induced section loss, enabling millimeter-scale three-dimensional …
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Low Proof Load Prediction of Ultimate Strengths of Fiberglass/Epoxy I-Beams Using Acoustic Emission
<p>Acoustic emission (AE) nondestructive testing was used to monitor fiberglass/epoxy I-beams. The experiment consisted of loading the I-beams in cantilever fashion with a hydraulic ram. While testing, AE waveforms were collected from the onset of loading to failure. After acquisition, the AE data …
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Neural Network Detection of Fatigue Crack Growth in Riveted Joints Using Acoustic Emission
… networks to discriminate between individual acoustic emission (AE) signals originating from crack growth and rivet rubbing (fretting) in aluminum lap joints. AE waveforms were recorded during tensile fatigue cycling of six notched and riveted 7075-T6 specimens using a broadband piezoelectric …
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Scale-model investigation of brittle tunnel failure using a true-triaxial device
… mock miniature tunnel boring machine (TBM), and acoustic emission (AE) monitoring, and (3) proposing more robust analytical methods and predictive models for brittle failures. The analog rock was designed to mimic the brittle behavior of sedimentary rock while maintaining a low uniaxial …
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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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Neural Network Fatigue Life Prediction in Notched Aluminum Specimens from Acoustic Emission Data
… bars under uniaxial tensile loading using acoustic emission (AE) data. The experiments performed in this study extend the results obtained by previous researchers who used maximum cyclic loads of 4,000, 3,000, and 2,000 pounds at a stress ratio of R = 0.0 and a frequency of 1 Hz to perform …
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Creep Damage Evolution in 316L Stainless Steel: Correlating Cavitation with Acoustic Emission
… voids. In parallel, the application of real-time acoustic emission (AE) sensing was employed to detect and analyse the elastic wave activity generated by microstructural failure phenomena and creep stages. Through the adept integration of statistical analysis of microstructural defects with …
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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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