Coherent Reflection and Transmission by a Randomly Cracked Elastic Slab

Angel, Y. C.; Bolshakov, A.

doi:10.1007/978-1-4615-5339-7_6

Cited by 2 publications

(2 citation statements)

References 7 publications

(13 reference statements)

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“…They consider, however, mostly point scatterers. In an e¬ort to extend the work of the preceding authors to nite-size scatterers, Angel & Koba (1998) and Angel & Bolshakov (1998) considered cracks of negligible thickness and nite length.…”

Section: Introductionmentioning

confidence: 99%

Antiplane coherent scattering from a slab containing a random distribution of cavities

Aguiar

Angel

2000

Proc. R. Soc. Lond. A

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The scattering of antiplane waves from a slab region containing a random distribution of cylindrical cavities is investigated. The cavities have a uniform probability density in the slab region and the solid is homogeneous and isotropic on either side of the slab. A general equation for the coherent motion in the solid is derived in terms of the average exciting displacement near a xed cavity. As in Foldy's approach, it is assumed here that the average exciting displacement near a xed cavity is equal to the average total displacement. With this assumption, the equation for the coherent motion reduces to an integrodi¬erential equation, which is solved in closed form by using a Fourier transform technique. The closed-form solution greatly reduces the computational costs, and allows more direct investigation of the multiple scattering than is done elsewhere. Results for the amplitudes and phases of the re®ected and transmitted waves outside the slab are plotted versus the frequency for several values of the cavity density and slab thickness. These results are expected to be valid for low cavity density.

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Section: Introductionmentioning

confidence: 99%

Antiplane coherent scattering from a slab containing a random distribution of cavities

Aguiar

Angel

2000

Proc. R. Soc. Lond. A

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“…Nonetheless, the T-mode LUT measurements are influenced by the distance between the source and receiver transducers, with short distances between the transducers reducing the reliability of the measured data due to the near-field effects and long distances between transducers (in combination with high wave frequencies) leading to difficulties in discriminating the onset of R-mode LUT has many potential applications in the field of rock engineering, as it can be used for (1) damage detection in critical rock engineering structures; (2) assessment of insufficient rebar and grout uniformity in grouted rock bolts; (3) evaluation of backfill grouting behind segmental linings in hard rock tunnels; and (4) passive detection of discontinuities and local features ahead of a tunnel face (Cui & Zou, 2012;Kravitz et al, 2019;Lee et al, 2009). However, R-mode LUT has seen limited study through fundamental laboratory-scale experiments, with most studies primarily focusing on models for simulating the wave-crack interaction processes (Angel & Achenbach, 1985;Angel & Bolshakov, 1998;Mikata, 1995;Pyrak-Nolte et al, 1990a, 1990bSchoenberg, 1980;Sotiropoulos & Achenbach, 1988). R-mode LUT was only recently implemented experimentally for continuously monitoring the dynamic processes associated with rock-joint frictional slipping phenomena (Hedayat, 2013;.…”

Section: Introductionmentioning

confidence: 99%

Illumination of Damage in Intact Rocks by Ultrasonic Transmission‐Reflection and Digital Image Correlation

2020

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Laboratory‐scale experiments on intact rocks are critical to the development of physics‐based fundamental understanding of various geophysical phenomena. In this work, the capability of ultrasonic wave transmission (T‐mode) and reflection (R‐mode) to monitor damage progression in uniaxially loaded prismatic intact rock specimens has been analyzed, as it is imperative to study the observations and document the capabilities of these techniques in a controlled environment. This study is novel in the sense that the R‐mode linear ultrasonic testing (LUT) has been rarely employed in studying intact rock damage processes in a laboratory setting, with most of the studies utilizing a direct transmission (T‐mode) approach or focusing on macroscopically fractured material. The two‐dimensional digital image correlation (2‐D DIC) full‐field strain measurement approach was also used in‐sync with the LUT monitoring to explicitly correlate the stress‐induced damage in the specimens with the changes observed in the ultrasonic (T‐mode and R‐mode) signals. The results show that both the T‐mode and R‐mode LUT approaches are sensitive to detect the evolution of tensile and shear damage in the specimens, with the R‐mode ultrasonic signals showing higher degree of sensitivity to the damage in the rocks, immediately following the initiation of damage in the rock volume.

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Coherent Reflection and Transmission by a Randomly Cracked Elastic Slab

Cited by 2 publications

References 7 publications

Antiplane coherent scattering from a slab containing a random distribution of cavities

Antiplane coherent scattering from a slab containing a random distribution of cavities

Illumination of Damage in Intact Rocks by Ultrasonic Transmission‐Reflection and Digital Image Correlation

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