SH Wave Propagation Research Articles

Seismic Response of a Shallow Asymmetrical V-Shaped Canyon with Cliffs under SH Waves Propagation

Seismic Response of a Shallow Asymmetrical V-Shaped Canyon with Cliffs under SH Waves Propagation

Exploring the influence of coupled interfacial imperfections on SH wave propagation in layered structures with sliding interaction

Exploring the influence of coupled interfacial imperfections on SH wave propagation in layered structures with sliding interaction

Effect of corrugation and rotation on SH wave propagation in an initially stressed functionally graded piezo-electric substrate

A rotating system that includes an initially stressed piezo-electric substrate was the subject of an analytical study of the SH waves. The substrate and vacuum bonding are in good contact with the corrugation, and the top border is treated as stress-free corrugation. About the upper barrier that is both electrically open as well as electrically short scenarios are taken into consideration. Dispersion equations for circumstances with a corrugated interface that are both electrically short as well as electrically open have been found. The SH wave characteristics through the framework suggested and circumstances dependent on different geometrical and physical factors have been investigated based on the numerical findings. The study looks at the simultaneous simulated outcomes of a number of physical factors that were produced in Mathematica 7 and include rotation, inhomogeneity, phase velocity, initial stress, and corrugated interface of SH wave distribution in a structure under discussion. The model under examination has potential applications in the creation of surface acoustic wave devices.

Comparative analysis of double and single porosity effects on SH-wave induced vibrations in periodic porous lattices

The manuscript presents a novel study comparing the impact of single and double porosity on horizontally polarized shear wave (SH-wave) propagation in corrugated elastic void materials. The considered mathematical model comprises two cases; the first one depicts SH-wave propagation through a void porous layer having creased boundaries and resting over a heterogeneous anisotropic fluid-saturated fractured porous half-space, whereas according to the second case, heterogeneous anisotropic fluid-saturated porous semi-infinite medium without fractures has been considered. In both cases, rigidity and density of the half-space vary quadratically with depth. The separable variable method is used to attain the complex frequency equation for each case that leads to two different dispersion relations associated with two distinct wave fronts. The first wave front depends on the void parameters, whereas the second wave front defines the propagation of SH-waves in an elastic layer without void pores. In each case, the complex dispersion relation has been separated into two equations that illustrate the dispersion and attenuation properties of SH-waves. Using the variations in the inhomogeneity, position, fluctuation, flatness, total porosity, and anisotropy parameters, case I and case II have been compared in each graphical execution. In addition, the surface response of shear stress and displacement have been implemented graphically.

Scattering of SH wave in an elastic half-space by a semi-elliptical crater with surface elasticity

Cratering occurs inevitably on the surface of materials at all scales due to comprehensive factors. The presence of craters may have a significant influence on the mechanical performance of the surface of an elastic body. In this paper, we study the SH wave propagation in an elastic semi-infinite medium whose surface has a semi-elliptical crater. We explore the scattering of the SH wave by the crater when surface elasticity is incorporated in the model of deformation to account for possible small-scale effects of the crater. We obtain a series solution for the scattered wave function by employing the Mathieu functions in the corresponding elliptical coordinate system. We discuss in some numerical examples the dynamic stress concentration around the crater relative to the wave frequency and few geometric parameters.

Propagation of SH-Wave in a Rotating Functionally Graded Magneto-Electro-Elastic Structure with Corrugated Interface

Propagation of SH-Wave in a Rotating Functionally Graded Magneto-Electro-Elastic Structure with Corrugated Interface

Weak bond evaluation of lap bonding structures by SH guided waves using EMATs

ABSTRACT In this research, simulations and experiments were conducted for the bonding quality evaluation of an aluminum bonding structure, based on the SH guided wave analysis. In order to simulate the propagation of SH waves in the bonded structure, a 3D finite element model was established based on interfacial spring stiffness modeling. The frequency-wavenumber diagram was obtained by doing Fourier transform along the spatial axis in the time frequency domain simulation results. At the same time, the influence of the bonding interface weakening on the propagation characteristics of the guided wave was analyzed. The simulated dispersion curves of SH-guided waves in different bonding states were in good agreement with the theoretically results. In addition, a periodic permanent magnet electromagnetic acoustic transducer (PPM-EMAT) 3D finite element model was established. An optimized transducer was fabricated to excite pure SH0 mode. Then, a series of aluminum lap bonding structures with different bonding states were prepared. The effect of bonding interfaces on the propagation characteristics of SH waves was investigated. The interfacial spring stiffness can be determined when the STFT of the SH waves matches the theoretical dispersion curves. Thus, this method demonstrated an ultrasonic way to distinguish the weakening of the bonding structures.

Propagation of SH Wave in a Rotating Functionally Graded Magneto-Electro-Elastic Structure with Imperfect Interface

Propagation of SH Wave in a Rotating Functionally Graded Magneto-Electro-Elastic Structure with Imperfect Interface

SH-Wave Propagation in Functionally Graded Magneto-Electro-Elastic Substrate at Irregular Boundaries

SH-Wave Propagation in Functionally Graded Magneto-Electro-Elastic Substrate at Irregular Boundaries

Scattering and reflection phenomena of SH-waves propagation through the surface irregularity in an orthotropic viscoelastic structure

Scattering and reflection phenomena of SH-waves propagation through the surface irregularity in an orthotropic viscoelastic structure

SH-Wave Propagation in Double Layers Imperfectly Bonded over a Dry Sandy Half-Space

SH-Wave Propagation in Double Layers Imperfectly Bonded over a Dry Sandy Half-Space

Nonlocal effect on shear wave propagation in a fiber-reinforced poroelastic layered structure subjected to interfacial impulsive disturbance

The present study illuminates the influence of impulsive line source on Horizontally polarized shear (SH) waves propagating in a stratified structure consisting of two distinct nonlocal fiber-reinforced layers with voids over a foundation with nonlocal functionally graded fiber-reinforced substrate with voids. The governing equations for a nonlocal fiber-reinforced poroelastic medium are established. The proposed mathematical model incorporates the Green’s function technique and the Fourier transformation to yield the complex dispersion relation of the propagating wave. The study discloses the existence of two wave fronts of SH-waves propagating with different speeds through the layered structure. The second wave front arises as a result of existence of void pores, while the first wave front defines SH-wave propagation in a nonlocal fiber-reinforced layered structure. Each wave front possesses individual critical frequency beyond which they fail to propagate. Speeds of both wave fronts are influenced by the appearance of nonlocality parameter. Using MATHEMATICA, several graphs have been plotted to demonstrate the impact of key parameters on the dispersion and attenuation of both wave fronts. Some notable cases have been derived which validate the present mathematical model.

Analytical study on the propagation of semi-infinite crack due to SH-wave in pre-stressed magnetoelastic orthotropic strip

This study deals with the propagation of semi-infinite crack impacted by SH-wave propagation in a pre-stressed magnetoelastic orthotropic strip (PMOS). The proposed analytical model makes use of the Wiener-Hopf (WH) approach and two-sided Fourier integral transforms (FIT). The exact formulation of the stress intensity factor (SIF) for constant concentrated force (CCF) has been established in closed form. The effect of influencing factors, including the crack length, crack speed, magnetoelastic parameter, horizontal compressive pre-stress (HCP)/horizontal tensile pre-stress (HTP), vertical compressive pre-stress (VCP)/vertical tensile pre-stress (VTP), and anisotropy parameter on the SIF in the considered strip has been unraveled. The proposed model is compared with the case of a pre-stressed magnetoelastic isotropic strip (PMIS) and some peculiarities, along with the influence of orthotropy have been reported. The significant results reported in the present manuscript reveal that magnetoelasticity and pre-stress is a prominent factor impacting crack propagation in elastic material with orthotropy configuration properties and has a significant impact on the SIF, which has not been taken into account in the existing literature on the subject of fracture mechanics. The present investigation helps with structural and reliability analysis, fracture propagation, material durability and failure of engineering structures.

Study of the dynamic electro-mechanical and microstructural behaviour on the elastic wave in FGM/FGPM composite structure: WKB asymptotic approach

This paper presents a theoretical investigation of the horizontally polarized shear wave in a composite structure. The assumed composite is composed of Functionally graded piezoelectric material (FGPM) layer constrained between an FGM (Functionally graded material) layer and a couple stress half-space with size-dependent microstructural effect. The variation in rigidities and densities are considered parabolic and linear in the upper and constrained layers, respectively. An analytical WKB (Wentzel–Kramers–Brillouin) asymptotic approach has been adopted for obtaining the dispersion relation. Also, a finite difference scheme (FDS) has been introduced to calculate the phase velocity and group velocity of the SH-wave. If waves travel in the time domain, it is necessary to check the accuracy and stability requirements. So that FDS has been adopted because of its accuracy, reliability, and flexibility. For the purpose of numerical calculation, three sets of FGPMs are considered namely, PZT−4, PZT−5H ceramic, and ceramic. Graphs have been plotted by means of dimensionless phase velocity against dimensionless wave number to show the effect of various parameters on the propagation of SH-wave. Numerical results demonstrated the accuracy and versatility of the phase and group velocity depending on the stability ratio of the FDS.

Time‐domain scaled boundary perfectly matched layer for elastic wave propagation

AbstractA novel artificial boundary method called the scaled boundary perfectly matched layer (SBPML) is proposed for the transient analysis of elastic wave propagation in unbounded domains. This method constructs a generalized perfectly matched layer (PML) around the finite interior subdomain based on a coordinate transformation inspired by the scaled boundary finite element method (SBFEM). It can model the infinite exterior subdomains of heterogeneous materials, featuring both parallel and radial straight‐line physical surfaces and interfaces. In addition, generally‐shaped (even nonconvex‐shape) artificial boundaries can be used to provide high flexibility in choosing the geometry of the finite interior subdomain. Two coordinate mapping technologies, namely the modified scaled boundary coordinate transformation from the SBFEM and the complex coordinate stretching from the PML, are successively utilized to construct the proposed method. By introducing the integral of stress as an auxiliary variable, the resulting SBPML subdomain is represented in the time domain using a mixed displacement‐stress unsplit‐field formulation. This has the added benefit of allowing for easy incorporation into standard dynamic finite element methods. The performance of the SBPML is demonstrated through several numerical examples, including P‐SV and SH wave propagation problems occurring in unbounded domains with complex geometries and heterogeneous material properties. The numerical results are evaluated in comparison to both reference solution and existing artificial boundary methods, ultimately demonstrating the flexibility, robustness, accuracy, and stability of the proposed approach.

Self-adaptive physics-driven deep learning for seismic wave modeling in complex topography

Solving for the scattered wavefield is a key scientific problem in the field of seismology and earthquake engineering. Physics-informed neural networks (PINNs) developed in recent years have great potential in possibly increasing the flexibility and efficacy of seismic modeling and inversion. Inspired by self-adaptive physics-informed neural networks (SA-PINNs), we introduce a framework for modeling seismic waves in complex topography The relevant theoretical model construction was performed using the one-dimensional (1D) wave equation as an example. Using SA-PINNs and combining them with sparse initial wavefield data formed by the spectral element method (SEM), we carry out a numerical simulation of two-dimensional (2D) SH wave propagation to realize typical cases such as infinite/semi-infinite domain and arc-shaped canyon/hill topography. For complex scattered wavefields, a sequential learning method with time-domain decomposition was introduced in SA-PINNs to improve the scalability and solution accuracy of the network. The accuracy and reliability of the proposed method to simulate wave propagation in complex topography were verified by comparing the displacement seismograms calculated by the SA-PINNs method with those calculated by the SEM. The results show that the SA-PINNs have the advantage of gridless and fine-grained simulation and can realize numerical simulation conditions, such as free surface and side-boundary wavefield transmission.

Strong motion estimation in Costa Rica at non-record sites using spectral inversion method

We performed the spectral inversion to separate the source, path, and site effects using strong ground motion records from essential facilities such as powerhouses and hydroelectric dams, distributed all over Costa Rica. The spectral inversion technique was adapted to a sparsely observed strong motion data set. We used the results to estimate strong ground motions at sites where there were no observation records in and around the intensity anomaly that appeared during the 2012 Sámara earthquake of Mw 7.6. To ensure the quality, we incorporated a broadband station to estimate levels of acceleration source spectra for six events 5.3 ≤ Mw ≤ 6.5, using them as the reference events for the spectral inversion. In this paper, we introduced two consistency checks: confirmation of the correctness of the input data, and verification of the output using synthetic spectra. We used them as an iterative implementation of sequences of elimination of suspicious data and inversions. We regulated the source spectra of the reference events for the final inversion, considering the estimate of site effect for one-dimensional SH wave propagation at the site of the lowest site amplification. We obtained the frequency-dependent quality factor Q = 179f0.5598 for the northern and central parts of Costa Rica. From the output of the spectral inversion, we reproduced the acceleration spectra of earthquakes in the sites where the event was not recorded. We applied this formulation using the earthquake mentioned above. The resulting synthetic spectra are consistent with the anomalous intensity distribution reported at that time.

Flexoelectric Effect on SH-Wave Propagation in Functionally Graded Fractured Porous Sedimentary Rocks with Interfacial Irregularity

Flexoelectric Effect on SH-Wave Propagation in Functionally Graded Fractured Porous Sedimentary Rocks with Interfacial Irregularity

The Behavior of Shear Waves in the Composite Multi-Material Structure with the Periodic Asymmetric Surfaces

The behavior of surface horizontally polarized shear waves (SH waves) in the composite multi-material structure with a periodic irregular surface and interface is investigated analytically in the present study. To unravel the enshrouded features of the SH-wave propagation in a multi-layer structure, we consider a model of three distinct composite materials. In the schematic of the problem, the guiding layer (M-I) contains fluid-saturated porous materials of finite thickness, the intermediate layer (M-II) contains fiber-reinforced composites, and the substrate contains the functionally graded orthotropic materials (M-III). The free surface of M-I and the upper interface of the medium are considered to be irregular on a periodic basis, but the interface of M-II and M-III is supposed to be regular. The dispersion relation is obtained analytically and demonstrated graphically for the phase velocity versus the wave number to analyze the propagation behavior of the SH-wave propagation in the proposed structure. The acquired results resemble the typical Love wave results, confirming the validity of the present work. The current work provides a comprehensive evaluation of the impact of regular and irregular boundaries of the composite materials on the phase velocity of the SH waves. It is notable that the behavior of the reinforced parameters, initial stress, and porosity on the phase velocity is consistent in both scenarios. More than the irregularity of the free surface, the periodic irregularity of the interface had an impact on the phase velocity. The obtained results are useful to understand the compositions of the materials on the mountain surface.

Characteristics of SH-wave propagation during oil reservoir excitation using BEM formulation in half-plane model representation

The application of elastic waves induced through seismic excitation (stimulation) to increase the oil recovery from a hydrocarbon reservoir as an enhanced oil recovery (EOR) technique is currently in its infancy. Seismic stimulation is a cost-effective and efficient method for enhancing oil production from waterflood reservoirs by increasing areal sweep performance and decreasing water cuts, hence extending the productive life of a mature oilfield. It has great prospect in offshore fields where technological difficulties and restrictions hinder the deployment of other EOR methods. Herein, this study investigates the effects of a direct impact of seismic SH-wave on a 2D transient behaviors of an oil reservoir with a half-plane model. In the time domain, a half-plane model containing a poroelastic oil reservoir is formulated using a boundary element method (BEM). The model considers complete seismic SH-wave propagation using Ricker wavelet, from a down-hole source via a partially saturated oil reservoir to ground surface receiving points. The model is based on 2D elastodynamic and Biot's dynamic poroelasticity equations. A DASBEM program is incorporated into MATLAB (2022a) to develop a model of wave propagation. The result showed that variable incidence angle affects the frequency and time domain responses, while the depth of the reservoir and porosity influence the amplitude of oscillation. Synthetic seismograms at stations above the oil reservoir indicated attenuation and numerous diffracted waves with various time delays. Multiple SH-wave reflections in the reservoir amplify 3D signals, while at higher dimensionless frequencies, effect of porosity amplify the distant locations. This technique can be utilized as fluid indicator to monitor wave based EOR using SH-wave attenuation, and to detect and visualize the permeability changes in reservoir (impermeable boundaries) during CO2 plume storage for the purpose of monitoring the safety of CO2 geo-sequestration.