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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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Journal ArticleDOI
TL;DR: In this paper, a new class of oxide/oxide composites made of Nextel™ 720 fiber reinforcement and a mullite-based matrix, fabricated by using liquid polymer infiltration process, were studied.
Abstract: In the present work, a new class of oxide/oxide composites made of Nextel™ 720 fibre reinforcement and a mullite-based matrix, fabricated by using liquid polymer infiltration process, were studied. A fibre coating was applied via sol–gel in order to achieve improved damage tolerant behaviour. Mechanical properties were investigated at ambient temperature under quasi-static loading in the presence of continuous Acoustic Emission (AE) monitoring. Statistical pattern recognition analysis is the proposed tool for the classification of the monitored AE events. Lacking an a priori knowledge of different signal classes, unsupervised pattern recognition algorithms were used. A complete methodology including descriptor selection methods, procedures for numerical verification and cluster validity criteria is followed. Cluster analysis of AE data was achieved and the resulted clusters were correlated to the damage mechanisms of the material under investigation. This process was assisted by systematic microscopic examination. Furthermore, the initiation and evolution of each mechanism is described by plotting the cumulative hits of each class as a function of the applied load.

93 citations

Journal ArticleDOI
TL;DR: In this article, the authors use a modal-style approach for the analysis of the exterior radiation characteristics of structures and show that the accuracy of the acoustic modal representation depends on the number of degrees of freedom in the radiation operator.
Abstract: The use of a modal‐style approach for the analysis of the exterior radiation characteristics of structures has recently received increasing attention. This approach generally seeks to find a set of orthogonal functions, or acoustic modes, that diagonalizes a radiation operator. These acoustic modes are found through an eigenfunction or singular value decomposition of the radiation operator. The eigenvalue or singular value associated with a given acoustic mode is directly proportional to the radiation efficiency of that acoustic mode. The acoustic mode represents a particular velocity pattern on the surface of the radiator. As with the analogous problem of finding structural natural frequencies and mode shapes, the accuracy of the acoustic modal representation depends on the number of degrees of freedom in the radiation operator. The radiation efficiency of the most efficient acoustic mode has a finite upper bound, and converges fastest with increasing degrees of freedom. Each additional degree of freedom in a model introduces a new least efficient acoustic mode. In fact, the radiation efficiency of the least efficient acoustic mode may be forced arbitrarily close to zero by introducing sufficient degrees of freedom. The most efficient acoustic modes are least sensitive to perturbations in their velocity patterns, while the least efficient acoustic modes are most sensitive. These characteristics of the exterior modal acoustic representation have significant implications for the use of the modal representation in design, optimization, and active noise control. This paper explores these issues using the example of a finite baffled beam.

93 citations

Journal ArticleDOI
TL;DR: In this article, the authors examined the performance of Li/MnO 2 cells with monitoring of particle fracture of manganese dioxide by acoustic emission, and found that particle fracture occurred during insertion into a solid matrix.
Abstract: Charge and discharge of Li/MnO 2 cells were examined with monitoring of particle fracture of manganese dioxide by acoustic emission. Manganese dioxide used was electrolytic manganese dioxide heat-treated at 400°C for 24 h in air [HEMD(400)]. The acoustic-emission technique worked well to monitor events that occurred inside a cell. During the first discharge to prepare a deep-discharge product, a closely packed series of acoustic events was observed, especially in the latter half of the discharge process, which contained most of the acoustic events. During cycling, acoustic events were concentrated at the end of discharge while no event was observed during charge, indicating that particle fracture took place during lithium-ion insertion into a solid matrix. Rate-capability tests showed that the rate of acoustic events was a function of current drain, i.e., a higher discharging current accelerated particle fracture. From these results we discuss the important role of mechanical properties of materials upon the lithium-insertion scheme. We also discuss the ideal considerations regarding insertion materials for advanced batteries.

93 citations

Journal ArticleDOI
TL;DR: In this article, the performance of six full-scale glass FRP bridge deck panels with nominal cross-sectional depths varying from 152 mm (6 in.) to 800 mm (30 in.).
Abstract: The application of fiber-reinforced composites (FRP) is gaining momentum as an alternative material for bridge replacement, repair, and rehabilitation. While a number of states now use FRP, a lack of standards, codes, and performance data for FRP bridge decks has resulted in the use of FRP technology not being widely accepted. This paper presents the performance results, based on acoustic emission (AE), of six full-scale glass FRP bridge deck panels with nominal cross-sectional depths varying from 152 mm (6 in.) to 800 mm (30 in.). The objective was to develop for use during in-service field inspections an AE monitoring strategy that will determine the structural performance of the deck. As such, the characterization of damage, e.g., fiber breakage, matrix cracking, and delamination, was part of the investigated criteria and the contributing factors for identification of a monitoring strategy. Although some factors were determined to be associated with the performance evaluation of the structural integrity of the decks, further investigation is needed.

92 citations

Journal ArticleDOI
TL;DR: In this article, the basic physical relationship between fracture processes and the acoustic emission waveforms accompanying them, have been examined to show that dynamic information about the magnitude and time-scale of fracture events can be deduced from measured waveforms.

92 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023701
20221,350
2021832
2020841
2019918
2018763