Ultrasonic investigation of granular materials subjected to compression and crushing

Gheibi, Amin; Hedayat, Ahmadreza

doi:10.1016/j.ultras.2018.02.006

Cited by 37 publications

(24 citation statements)

References 71 publications

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“…Thus, if the average contact force decreases the shear strength of the material, stress drop and radiated acoustic energy should all decrease. This explanation is in good agreement with our data and is also consistent with previous works (Gheibi & Hedayat, 2018). This implies that in addition to fault slip velocity, the total number of contact junctions per unit volume (i.e., the true contact area) plays a key role in the generation of acoustic energy.…”

Section: Discussionsupporting

confidence: 94%

Acoustic Energy Release During the Laboratory Seismic Cycle: Insights on Laboratory Earthquake Precursors and Prediction

et al. 2020

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Machine learning can predict the timing and magnitude of laboratory earthquakes using statistics of acoustic emissions. The evolution of acoustic energy is critical for lab earthquake prediction; however, the connections between acoustic energy and fault zone processes leading to failure are poorly understood. Here, we document in detail the temporal evolution of acoustic energy during the laboratory seismic cycle. We report on friction experiments for a range of shearing velocities, normal stresses, and granular particle sizes. Acoustic emission data are recorded continuously throughout shear using broadband piezo‐ceramic sensors. The coseismic acoustic energy release scales directly with stress drop and is consistent with concepts of frictional contact mechanics and time‐dependent fault healing. Experiments conducted with larger grains (10.5 μm) show that the temporal evolution of acoustic energy scales directly with fault slip rate. In particular, the acoustic energy is low when the fault is locked and increases to a maximum during coseismic failure. Data from traditional slide‐hold‐slide friction tests confirm that acoustic energy release is closely linked to fault slip rate. Furthermore, variations in the true contact area of fault zone particles play a key role in the generation of acoustic energy. Our data show that acoustic radiation is related primarily to breaking/sliding of frictional contact junctions, which suggests that machine learning‐based laboratory earthquake prediction derives from frictional weakening processes that begin very early in the seismic cycle and well before macroscopic failure.

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Section: Discussionsupporting

confidence: 94%

Acoustic Energy Release During the Laboratory Seismic Cycle: Insights on Laboratory Earthquake Precursors and Prediction

et al. 2020

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“…This increase in the amplitude is consistent with the reduction in the total apparent tensile strain ε T AT in the same stress regime (see Figure a). The reduction in ε T AT is associated with material hardening which increases the contact area between the grains of the rocks, resulting in an increase in the transmission of the ultrasonic wave amplitude (Gheibi & Hedayat, ; Liu & Nagel, ). Amplitude attenuation in the ultrasonic waves starts to increase with an increase in the stress magnitude applied on the specimens (30% to 70% of the UCS).…”

Section: Resultsmentioning

confidence: 99%

“…The prismatic shape of specimens has been chosen to ensure a planar surface necessary for accurate in-plane 2D-DIC measurements (Ferrero et al, 2008;Sutton et al, 2009). Extensive work has been performed using LUT as a tool for diagnosing the state of damage in various applications (Acosta-Colon et al, 2009;Cai & Zhao, 2000;Ghazvinian, 2015;Gheibi & Hedayat, 2018;Hedayat et al, 2014a;Hedayat et al, 2018;Hildyard et al, 2005;Huang et al, 2014;Jones, 1952;Modiriasari et al, 2017;Pyrak-Nolte, 1988;Sayers et al, 1990;Scott et al, 1993;Suaris & Fernando, 1987;Yang et al, 2018;Zhao et al, 2006). Significant efforts have been made to analytically model the effects of cracks and fractures on the ultrasonic wave propagation (Blum et al, 2011;Chaix et al, 2006;Crampin et al, 1980;De Basabe et al, 2016;Gross & Zhang, 1992;O'Connell & Budiansky, 1974;Hudson, 1981;Piau, 1979;Pyrak-Nolte et al, 1990a, 1990bWaterman & Truell, 1961;Yang & Turner, 2003).…”

Section: Introductionmentioning

confidence: 99%

Experimental Relationship Between Compressional Wave Attenuation and Surface Strains in Brittle Rock

2019

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Linear ultrasonic testing (LUT) has been extensively used as a tool for the evaluation of damage processes in various materials ranging from synthetic metals to natural geomaterials, such as rocks. A key limitation of LUT‐based damage studies to date is the lack of explicit evidence used in associating material damage with the changes in measured LUT attributes (e.g., ultrasonic wave amplitude and velocity). In this study, the evolution of the full‐field strains in brittle rock specimens (Lyons sandstone) subjected to failure are analyzed in real time and linked with the changes in the ultrasonic wave amplitude in localized areas illuminated by ultrasonic beams, termed as the ultrasonic image areas. The noncontact optical full‐field displacement measurement method of 2‐D digital image correlation is implemented in combination with the LUT procedure to continuously track changes in the ultrasonic wave amplitude with the evolution of strains across the surface of the uniaxially loaded intact rock specimens. The ultrasonic amplitude showed near‐linear correlation with the intensity of inelastic tensile strain recorded in the rock specimens. The results from the study corroborate that the ultrasonic changes are in fact influenced by the regions of tensile cracking, which is the primary inelastic deformation mechanism in brittle rocks.

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“…The pressureinduced transition of power-law exponent ranging from 1/4 to 1/6 has also been observed not only for randomly packed spheres (12,28,29) but also, for natural geomaterials, including dry and water-saturated soils and sands, under both preconsolidation and overconsolidation (28,(30)(31)(32)(33). This transition has been qualitatively attributed to the deformation of interparticle asperities (28), force chain arrangements (27,28,33), stress heterogeneity (32,34), packing reorganization (12,16,29), nonspherical contact geometries (27,32), wave modes (such as compressional and shear wave), and wave amplitudes (12,32,33,35). However, a study quantitatively linking packing structure disorder and contact force heterogeneity to wave velocity and velocity scaling in 3D disordered granular materials has not yet been performed.…”

mentioning

confidence: 82%

“…Here, the exponent value of 1/6 corresponds to theoretical predictions of Hertzian contact and has been confirmed in solitary wave propagation experiments on 1D chains of spherical particles ( 8 ). The pressure-induced transition of power-law exponent ranging from 1/4 to 1/6 has also been observed not only for randomly packed spheres ( 12 , 28 , 29 ) but also, for natural geomaterials, including dry and water-saturated soils and sands, under both preconsolidation and overconsolidation ( 28 , 30 – 33 ). This transition has been qualitatively attributed to the deformation of interparticle asperities ( 28 ), force chain arrangements ( 27 , 28 , 33 ), stress heterogeneity ( 32 , 34 ), packing reorganization ( 12 , 16 , 29 ), nonspherical contact geometries ( 27 , 32 ), wave modes (such as compressional and shear wave), and wave amplitudes ( 12 , 32 , 33 , 35 ).…”

mentioning

confidence: 82%

The influence of packing structure and interparticle forces on ultrasound transmission in granular media

Zhai

Herbold

Hurley

2020

Proc. Natl. Acad. Sci. U.S.A.

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Ultrasound propagation through externally stressed, disordered granular materials was experimentally and numerically investigated. Experiments employed piezoelectric transducers to excite and detect longitudinal ultrasound waves of various frequencies traveling through randomly packed sapphire spheres subjected to uniaxial compression. The experiments featured in situ X-ray tomography and diffraction measurements of contact fabric, particle kinematics, average per-particle stress tensors, and interparticle forces. The experimentally measured packing configuration and inferred interparticle forces at different sample stresses were used to construct spring networks characterized by Hessian and damping matrices. The ultrasound responses of these network were simulated to investigate the origins of wave velocity, acoustic paths, dispersion, and attenuation. Results revealed that both packing structure and interparticle force heterogeneity played an important role in controlling wave velocity and dispersion, while packing structure alone quantitatively explained most of the observed wave attenuation. This research provides insight into time- and frequency-domain features of wave propagation in randomly packed granular materials, shedding light on the fundamental mechanisms controlling wave velocities, dispersion, and attenuation in such systems.

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Ultrasonic investigation of granular materials subjected to compression and crushing

Cited by 37 publications

References 71 publications

Acoustic Energy Release During the Laboratory Seismic Cycle: Insights on Laboratory Earthquake Precursors and Prediction

Acoustic Energy Release During the Laboratory Seismic Cycle: Insights on Laboratory Earthquake Precursors and Prediction

Experimental Relationship Between Compressional Wave Attenuation and Surface Strains in Brittle Rock

The influence of packing structure and interparticle forces on ultrasound transmission in granular media

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