Predicting failure in solids has broad applications including earthquake prediction which remains an unattainable goal. However, recent machine learning work shows that laboratory earthquakes can be predicted using micro-failure events and temporal evolution of fault zone elastic properties. Remarkably, these results come from purely data-driven models trained with large datasets. Such data are equivalent to centuries motion rendering application tectonic faulting unclear. In addition, the...

Elastodynamic metasurfaces composed of surface-mounted resonators show great promise for guided wave control in diverse applications, e.g., seismic and vibration isolation, nondestructive evaluation, or surface acoustic devices. In this work, we revisit the well-studied problem “rod-shaped” coupled to a plate reveal relationship between resonator's resonances antiresonances obtained under unidirectional harmonic excitation, resultant frequency bandgap S0 Lamb mode propagation once...

Abstract Dynamic acoustoelastic testing is performed on a set of six rock samples (four sandstones, one soapstone, and granite). From these studies at 20 strain levels 10 −7 < ϵ <10 −5 , four measures characterizing the nonlinear elastic response each sample are found. Additionally, tested with resonant ultrasonic spectroscopy fifth measure These five (approximately 3 × 6×20 5 numbers as measurement repeated times) subjected to careful analysis using model‐independent statistical...

Dispersion curves are essential to any guided-wave-related project. The Semi-Analytical Finite Element (SAFE) method has become the conventional way compute dispersion for homogeneous waveguides. However, only recently a general SAFE formulation commercial and open-source software available, meaning that until now analyses have been variable more time consuming than desirable. Likewise, Floquet boundary conditions enable analysis of waveguides with periodicity an integral part development...

Research Article| March 06, 2019 Characterizing Acoustic Signals and Searching for Precursors during the Laboratory Seismic Cycle Using Unsupervised Machine Learning David C. Bolton; Bolton aDepartment of Geosciences, Pennsylvania State University, 201 Old Main, University Park, 16802 U.S.A., dcb31@psu.educhrisjmarone@gmail.com Search other works by this author on: GSW Google Scholar Parisa Shokouhi; Shokouhi bDepartment Engineering Science Mechanics, pxs990@psu.edu, jvr5626@psu.edu Bertrand...

We link changes in crustal permeability to informative features of microearthquakes (MEQs) using two field hydraulic stimulation experiments where both MEQs and evolution are recorded simultaneously. The Bidirectional Long Short-Term Memory (Bi-LSTM) model effectively predicts ultimate increase. Our findings confirm the form key linking permeability, offering mechanistically consistent interpretations this association. Transfer learning correctly one experiment from a trained on an alternate...

Dynamic acousto-elastic testing, a pump-probe scheme, is employed to investigate the recovery of consolidated granular media systems from non-equilibrium steady state established by pump strain field. This measurement scheme makes it possible follow over many orders magnitude in time. The described with relaxation time spectrum that found be independent amplitude (pump amplitude) and environment which samples reside. its slow are laboratory realization phenomena physical practical importance.

Abstract Acoustoelasticity measurements in a sample of room dry Berea sandstone are conducted at various loading frequencies to explore the transition between quasi‐static ( ) and dynamic (few kilohertz) nonlinear elastic response. We carry out these multiple confining pressures perform multivariate regression analysis quantify dependence harmonic content on strain amplitude, frequency, pressure. The modulus softening (equivalent 0 f increases by factor 2–3 over 3 orders magnitude increase...

Abstract Small changes in seismic wave properties foretell frictional failure laboratory experiments and some cases on faults. Such precursors include systematic velocity amplitude throughout the cycle. However, relationships between features shear stress are complex. Here, we use data from lab friction that continuous measurement of elastic waves traversing fault build data‐driven models to learn these complex relations. We demonstrate deep learning accurately predict timing size...

Abstract We present a theoretical model and experimental evidence of the long‐time relaxation process (slow dynamics) in rocks other geomaterials following dynamic wave excitation, at scales ranging from laboratory to Earth. The is based on slow recovery an ensemble grain contacts asperities broken by mechanical impact. It includes Arrhenius‐type equation for metastable, contacts. provides characteristic size (order 10 −9 m) predicts that their number increases with impact amplitude....

The changes in the sonic surface wave velocity of concrete under stress were investigated this paper. Surface velocities at frequency range measured on a prismatic specimen undergoing several cycles uniaxial compression. loading was applied (or removed) gradually predefined small steps (stress-controlled). every load step during both and unloading phases. Acoustic Emission (AE) test conducted simultaneously to monitor microcracking activities different levels loading. It found that is highly...

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The accuracy and precision of low-frequency (center frequency approximately 55 kHz) ultrasonic testing for detection characterization delamination in concrete bridge decks were evaluated. A multiprobe system (with horizontally polarized shear-wave transducers) was used to detect built-in defects various size, depth, severity (i.e., thickness) a test specimen—a 6.1 m×2.4 m×216 mm (20 ft×8 ft×8.5 in.) reinforced slab-built simulate deck. collected data sets reconstructed applying synthetic...

Nonlinearity of damaged materials is often assumed to be correlated with the cumulative length micro-cracks discounting influence crack width and roughness. To investigate microstructural features realistic cracks on nonlinear elastic properties, Dynamic Acousto-Elastic Testing (DAET) performed two aluminum alloy samples (30 × 40 170 mm3) a single fatigue-crack. The are similar but have dissimilar due different stress intensity factors used during fatigue tests. DAET carried out surface wave...

Tectonic faults fail through a spectrum of slip modes, ranging from slow aseismic creep to rapid during earthquakes. Understanding the seismic radiation emitted these modes is key for advancing earthquake science and hazard assessment. In this work, we use laboratory friction experiments instrumented with ultrasonic sensors document properties fast Stick-slip were conducted at constant loading rate 8 μm/s normal stress was systematically increased 7 15 MPa. We produced full by modulating...