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 article, acoustic emission (AE) monitoring of 36 steel railroad bridges is presented to find new cracks, identify active cracks, validate the effectiveness of repairs, and to provide damage assessments to assist with repair prioritization.
Abstract: Results from acoustic emission (AE) monitoring of 36 steel railroad bridges are presented. The demonstrated successes of using AE to find new cracks, to identify active cracks, to validate the effectiveness of repairs, and to provide damage assessments to assist with repair prioritization are discussed. The challenges presented in using AE for fatigue-life estimation; for the assessment of pins, hangers, and complex weldments; and for crack assessment of severely corroded members are outlined. Finally, new ideas for refined monitoring and enhanced data analysis are presented.
63 citations
TL;DR: In this paper, the authors presented a computational study of the flow and flow-induced acoustic fields of a supersonic jet impinging on an inclined flat plate, and analyzed the simulation results mainly from the viewpoint of the acoustic emission and propagation mechanism, and investigated the acoustic field characteristics such as directivity, their spectra and acoustic wave source positions.
Abstract: This paper presents a computational study of the flow and flow-induced acoustic fields of a supersonic jet impinging on an inclined flat plate. For the numerical simulations, we solved three-dimensional compressible Navier-Stokes equations with a modified weighted compact nonlinear scheme. We analyzed the simulation results mainly from the viewpoint of the acoustic emission and propagation mechanism, and we investigated the acoustic field characteristics such as directivity, their spectra, and acoustic wave source positions. The acoustic fields indicate that there are at least three types of acoustic waves in all the cases considered in the study: (i) Mach waves generated from the shear layer of the main jet, (ii) acoustic waves generated from the impingement region, and (iii) Mach waves generated from the shear layer of the supersonic flow downstream of the jet impingement. The indication of the second type of wave (ii) is important because the commonly used empirical method for the estimation of the aco...
63 citations
TL;DR: In this paper, the authors carried out a series of flow-through triaxial compression tests on porous sandstones at different temperatures and strain rates and found that significant AE activity starts less than 5 min before sample failure irrespective of the strain rate.
Abstract: [1] Little is known about the temperature and strain rate dependence of acoustic emission AE activity (AE). Hence, we carried out a preliminary series of flow-through triaxial compression tests on porous sandstones at different temperatures and strain rates. The AE data exhibits clear foreshock and aftershock sequences with respect to the dynamic failure of the test specimen. Significant AE activity starts less than 5 min before sample failure irrespective of the strain rate. The increase in the AE event rate is steeper and the foreshock exponent p′ is smaller in the slow strain rate tests. It could be the reason why there are no easily recognisable foreshock sequences for most individual earthquakes. The aftershock decay parameter p is a linear function of test temperature as it has also been inferred for natural seismicity. The seismic b-value decreases systematically with increasing deformation rate suggesting a greater proportion of small cracks in the slow strain rate tests. Hence, the AE activity is a function of both strain rate and temperature.
63 citations
TL;DR: In this paper, the epicentre location of an elastic half-space has been calculated for force dipoles and combinations of forces representing the formation of point microcracks, the motion of dislocations and dilatation sources.
Abstract: Acoustic emission waveforms for the epicentre location of an elastic half-space have been calculated for force dipoles and combinations of force dipoles representing the formation of point microcracks, the motion of dislocations and dilatation sources. The effects of source orientation, depth and time dependence are shown graphically. These results are used to emphasise the features of acoustic emission signals and their frequency spectra that must be accurately measured if dynamic information or the source type are to be deduced.
63 citations
TL;DR: In this paper, the deterioration mechanism and fatigue fracturing evolution of granite with two pre-existing flaws experiencing freeze-thaw (F-T) treatment are investigated in an open pit slope In-situ acoustic emission monitoring combined with the post-test 3D computed tomography (CT) technique was employed to reveal the fracture evolution behaviors of rock treated with 0, 50, and 80 F-T cycles.
63 citations