Acoustic emission at failure in quasi-brittle materials

Labuz, Joseph F.; Cattaneo, Sara; Chen, Li Hsien

doi:10.1016/s0950-0618(00)00072-6

Cited by 85 publications

(28 citation statements)

References 9 publications

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“…Maji and Shah (1988), for example, determined the fracture process zone in pre-cracked concrete specimens under tension by means of the source location of acoustic emissions. Labuz et al (2001) quantified the intrinsic process zone in cementitious specimens of various size subjected to diametral compression (Brazilian-disc test) and 3PB. The dimensions of the fracture process zone based on the location of the acoustic events were determined also for rock specimens (Muralidhara et al, 2010).…”

Section: Acoustic Emissionsmentioning

confidence: 99%

Mechanical response of notched marble beams under bending versus acoustic emissions and electric activity

Kourkoulis

Pasiou

Dakanali

et al. 2018

jtam

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An experimental protocol, including the combined application of both innovative and traditional sensing techniques, is described aiming to explore the mechanical response of marble and also to check the possibilities of detecting precursor phenomena designating upcoming catastrophic fracture. The protocol consisted of three-point bending tests with notched prismatic beams made of Dionysos marble, the material extensively used for restoration of the Acropolis of Athens monuments. The sensing system improvised included techniques relying on completely different physical foundations, which permit simultaneous detection and recording of the Pressure Stimulated Currents, Acoustic Emissions, three dimensional displacement fields and Notch Mouth Opening Displacements. Analysis of the results revealed interesting features of the mechanical response of Dionysos marble and indicated, also, that classical Continuum Fracture Mechanics fails to describe accurately the response of marble, at least in the presence of notches. In addition, strong correlations between the Pressure Stimulated Currents, the rate of acoustic hits and the rate of change of the opening of the pre-existing notch have been enlightened. Moreover, the onset of catastrophic crack propagation appears following distinguishable changes of the Pressure Stimulated Currents recorded. Therefore (and taking into account the very small size of the respective sensors as well as the simple complementary equipment needed), it is concluded that the specific technique could be considered as a simple and reliable tool for an alternative approach to the in-situ Structural Health Monitoring of classical stone monuments.

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Section: Acoustic Emissionsmentioning

confidence: 99%

Mechanical response of notched marble beams under bending versus acoustic emissions and electric activity

Kourkoulis

Pasiou

Dakanali

et al. 2018

jtam

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show abstract

“…More quantitative analysis is possible, with a number of listening transducers, through event location and source mechanism analysis. The former can highlight the transition from distributed to localised deformation that might indicate the onset of macroscopic failure (e.g., LOCKNER et al, 1991;ZANG et al, 1998;LABUZ et al, 2001;STANCHITS and DRESEN, 2003;LEI et al, 2004). Source mechanism analysis, based on received amplitude polarities, provides insight into the failure mode, such as shear versus dilation, and the sense of movement (e.g., ZANG et al, 1998;LEI et al, 2000).…”

Section: Acoustic Emission (Ae) Monitoring Of Rock Failure and Fractumentioning

confidence: 99%

Monitoring Fracture Propagation in a Soft Rock (Neapolitan Tuff) Using Acoustic Emissions and Digital Images

Hall

Sanctis

Viggiani

2006

Pure appl. geophys.

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Sudden and unexpected collapses of underground cavities below the city of Naples (Italy) represent a serious safety hazard. The collapses occur due to the detachment of large blocks from the cavity roofs, walls and pillars, often a long time after the original quarry excavation has been completed. It is recognised that existing discontinuities, e.g., fractures, play an important role in the failure process by inducing local stress-concentrations and reducing the overall material strength. The larger fractures, which ultimately lead to collapse occur through interaction, propagation and coalescence of these discontinuities. This paper presents recent results of experiments carried out on natural, dry specimens of Neapolitan finegrained tuff to investigate the mechanisms involved in sample failure. A better understanding of fracture development and rock bridge behaviour is gained through a combination of AE and photographic monitoring in an experimental program considering samples with artificial pre-existing heterogeneities, which simulate the in situ discontinuities. For a range of rock bridge geometries the mechanisms and timing of different stages of the failure process are identified and characterised. The results show that, in general, a classical description of failure, for samples without artificial flaws or with only a single flaw, is followed: (1) crack closure; (2) linear stress-strain response and crack initiation with stable crack growth; (3) crack damage and unstable crack growth leading to failure. For samples with two artificial pre-existing flaws the third phase is split into two parts and failure of the sample occurs only after both the unstable propagation of external wing cracks and coalescence of the internal cracks in the bridge. In terms of the timing and duration of each phase, it is seen that phases 1 and 2 have little dependence on the flaw configuration but phase 3 seems to depend directly on this. In particular the angle in rock bridge between the inner tips of the pre-existing flaws, b, plays a key role: phase 3 is shorter for b = 120°than for b = 105°. These differences are due to the different modes of coalescence in the rock bridge. For b = 105°the total failure is preceded by bridge rotation, which appears to take longer than the simpler mode of failure for b = 120°. It has only been possible to determine the time ranges of interest using the AE signatures, whilst the photographs allow the fracture geometry evolution to be described. Additionally the frequency character of AE events is investigated and shown to have significant potential for characterisation of AE source types and thus failure processes.

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“…The crack propagation process releases energy as elastic waves, known as acoustic emission, AE [2]. Given the characteristics of the initiation of this damage process, experimental analyses of specimens subjected to tensile stresses monitored with AE is an adequate option to achieve a real understanding of this process.…”

Section: Introductionmentioning

confidence: 99%

“…Several works have reported on the three-dimensional localization of AE sources [2][3][4][5][6][7], but they consider vp as a known value that remains unchanged while damage is induced in the specimen. This assumption is not realistic and may affect the accuracy of the localization process and the accuracy of the AE sources pattern obtained.…”

Section: Introductionmentioning

confidence: 99%

Assessment of Damage Distribution in Brittle Materials by Application of an Improved Algorithm for Three-Dimensional Localization of Acoustic Emission Sources with P-Wave Velocity Calculation

Rodríguez¹,

Celestino

2018

The 18th International Conference on Experimental Mechanics

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Abstract:The rupture process in brittle materials is associated with tensile stresses at microscopic flaw scale inside their volume. Acoustic emission monitoring of diametral compression tests is an adequate option to assess the progression of damage. An improved algorithm for AE sources localization with P-wave velocity, vp, calculation and an enhanced methodology for P-wave onset time, called CLAPWaVe (Rodríguez 2015), is applied to analyze the distribution of damage and the evolution of stiffness within monzogranite specimens. Complementary analyses allowed the identification of four zones of damage accumulation within the specimen volume, each of them with different cracking levels, absolute energy release, EA, associated vp values, induced by different phenomena occurring during the loading process. The observed non-homogeneous damage distribution confirms that using a unique vp value to perform the localization of all AE sources, as usually adopted, is not representative of the real condition of the specimen.

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Acoustic emission at failure in quasi-brittle materials

Cited by 85 publications

References 9 publications

Mechanical response of notched marble beams under bending versus acoustic emissions and electric activity

Mechanical response of notched marble beams under bending versus acoustic emissions and electric activity

Monitoring Fracture Propagation in a Soft Rock (Neapolitan Tuff) Using Acoustic Emissions and Digital Images

Assessment of Damage Distribution in Brittle Materials by Application of an Improved Algorithm for Three-Dimensional Localization of Acoustic Emission Sources with P-Wave Velocity Calculation

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