Mechanical and Electromagnetic Emissions Related to Stress-Induced Cracks

Carpinteri, Alberto; Lacidogna, Giuseppe; Manuello, A.; Niccolini, Gianni; Schiavi, Alessandro; Agosto, A.

doi:10.1111/j.1747-1567.2011.00709.x

Cited by 79 publications

(38 citation statements)

References 27 publications

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“…This satisfactory correlation is consistent with the results of other researchers [27][28][29][30]. Since in the specimens subjected to seismic loading, the forces were applied dynamically in successive seismic simulations, only macroscopic cracks were observed at the end of each one.…”

Section: Rc Framesupporting

confidence: 81%

Correlation of Plastic Strain Energy and Acoustic Emission Energy in Reinforced Concrete Structures

et al. 2016

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This paper presents a comparison of the acoustic emission (AE) energy and the plastic strain energy released by some reinforced concrete (RC) specimens subjected to cyclic or seismic loadings. AE energy is calculated, after proper filtering procedures, using the signals recorded by several AE low frequency sensors (25-100 kHz) attached on the specimens. Plastic strain energy is obtained by integrating the load displacement curves drawn from the measurements recorded during the test. Presented are the results obtained for: (i) two beams (with and without an artificial notch) and a beam-column connection subjected to several cycles of imposed flexural deformations; (ii) a reinforced concrete slab supported by four steel columns, and a reinforced concrete frame structure, both of the latter are subjected to seismic simulations with a uniaxial shaking table. The main contribution of this paper, which is a review of some papers previously published by the authors, is to highlight that, in all cases, a very good correlation is found between AE energy and plastic strain energy, until the onset of yielding in the reinforcing steel. After yielding, the AE energy is consistently lower than the plastic strain energy. The reason is that the plastic strain energy is the sum of the contribution of concrete and steel, while the AE energy acquired with thresholds higher than 35 dB AE captures only the contribution of the concrete cracking, not the steel plastic deformation. This good correlation between the two energies before the yielding point also lends credibility to the use of AE energy as a parameter for concrete damage evaluation in the context of structural health monitoring.

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Section: Rc Framesupporting

confidence: 81%

Correlation of Plastic Strain Energy and Acoustic Emission Energy in Reinforced Concrete Structures

et al. 2016

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“…This leads to an asymmetric charge separation for a reason that is still not fully understood [12]. It has to be noted that this break of symmetry is questioned by some authors [2,4,21]. However, similar effects are known for other dielectric solids [22].…”

Section: Introductionmentioning

confidence: 94%

Relation of Electromagnetic Emission and Crack Dynamics in Epoxy Resin Materials

et al. 2014

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Electromagnetic emission (EME) testing and acoustic emission (AE) testing are applied to investigate the failure of a brittle, dielectric material under mechanical load. A setup for three point flexure tests comprising simultaneous monitoring of EME and AE was used to induce fracture of epoxy resin specimens. The influences of the orientation and the distance of the crack surface on the detectable EME signals are the subjects of investigation. As EME sensor a capacitive sensor was used. Tests with an artificial test source are carried out to characterize the system response of the sensor, the attached amplifier and acquisition cards as well as the included bandpass filters. We propose an EME source based on the surface charge density modelled at the position of the fracture plane. Results of finite element method modelling of the EME source are compared to experimental results and show very good agreement. The experimental results show a clear directional character of the emitted electromagnetic field and a strong dependence of the detected signals amplitude on sourcesensor distance. A significant influence of the measurement chain on the detected electromagnetic signals bandwidth was found. Furthermore it is shown that the electromagnetic signals consist of three contributions originating from different source mechanisms. These are attributed to the separation and

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“…Indeed, laboratory studies suggest that the strong avalanche-like EM signals are generated only during sharp drops in stress, while the amplitude of the emitted EM fields is proportional to the stress rate (Fukui, 2005;Carpinteri et al, 2011Carpinteri et al, , 2012. These sharp drops are attributed to a rapid decay of the mechanical properties, generated by formation of new micro-cracks during the loading process (Carpinteri et al, 2012).…”

Section: Focus On the First Phasementioning

confidence: 99%

“…However, recent accumulated laboratory evidence indicates that the recorded AE and EME, in general, are not two sides of the same coin. There are two categories of AE signals -namely AE signals that are associated with EME signals, and AE signals that are not associated with EME signals (e.g., Yamada et al, 1989;Rabinovitch et al, 1995;Morgounov, 2001;Mori et al, 1994Mori et al, , 2004aMori et al, , b, 2006Mori et al, , 2009Mori and Obata, 2008;Lacidogna et al, 2010;Baddari and Frolov, 2010;Baddari et al, 2011;Carpinteri, 2012). Importantly, laboratory experiments performed recently reveal that the final stage of the failure process coincided in time with the maximum of AE and quiescence in EME, while strong avalanche-like EME precedes this phase (Morgounov, 2001;Baddari et al, 2011).…”

Section: Are the Ae And Eme Two Sides Of The Same Coin?mentioning

confidence: 99%

“…More specifically, electromagnetic emissions (EME) and acoustic emissions (AE) in a wide frequency spectrum ranging from the kHz to the MHz bands are produced by opening cracks, which can be considered as the so-called precursors of general fracture. Recently, improvements in the MHz-kHz EME technique have permitted a real-time monitoring of the fracture process (Fukui et al, 2005;Kumar and Misra, 2007;Chauhan and Ashok Misra, 2008;Baddari et al, 1999Baddari et al, , 2011Baddari and Frolov, 2010;Lacidogna et al, 2010;Schiavi et al, 2011;Carpinteri et al, 2012). However, the MHz-kHz electromagnetic (EM) precursors are detectable not only at the laboratory but also at the geological scale; a stressed rock behaves like a stress-EM transducer (Sadovski, 1982;Hayakawa and Fujinawa, 1994;Gokhberg et al, 1995;Hayakawa, 1999Hayakawa, , 2009Hayakawa and Molchanov, 2002;Eftaxias et al, 2007Eftaxias et al, , 2011Eftaxias, 2012;Molchanov and Hayakawa, 2008).…”

Section: Introductionmentioning

confidence: 99%

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On the puzzling feature of the silence of precursory electromagnetic emissions

Eftaxias

Potirakis

Chélidzé

2013

Nat. Hazards Earth Syst. Sci.

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Abstract. It has been suggested that fracture-induced MHzkHz electromagnetic emissions (EME), which emerge from a few days up to a few hours before the main seismic shock occurrence permit a real-time monitoring of the damage process during the last stages of earthquake preparation, as it happens at the laboratory scale. Despite fairly abundant evidence, electromagnetic (EM) precursors have not been adequately accepted as credible physical phenomena. These negative views are enhanced by the fact that certain "puzzling features" are repetitively observed in candidate fractureinduced pre-seismic EME. More precisely, EM silence in all frequency bands appears before the main seismic shock occurrence, as well as during the aftershock period. Actually, the view that "acceptance of "precursive" EM signals without convincing co-seismic signals should not be expected" seems to be reasonable. In this work we focus on this point. We examine whether the aforementioned features of EM silence are really puzzling ones or, instead, reflect well-documented characteristic features of the fracture process, in terms of universal structural patterns of the fracture process, recent laboratory experiments, numerical and theoretical studies of fracture dynamics, critical phenomena, percolation theory, and micromechanics of granular materials. Our analysis shows that these features should not be considered puzzling.

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Mechanical and Electromagnetic Emissions Related to Stress-Induced Cracks

Cited by 79 publications

References 27 publications

Correlation of Plastic Strain Energy and Acoustic Emission Energy in Reinforced Concrete Structures

Correlation of Plastic Strain Energy and Acoustic Emission Energy in Reinforced Concrete Structures

Relation of Electromagnetic Emission and Crack Dynamics in Epoxy Resin Materials

On the puzzling feature of the silence of precursory electromagnetic emissions

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