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Wave Propagation in Two-Dimensional Isotropic Waveguides
Published in Srinivasan Gopalakrishnan, Elastic Wave Propagation in Structures and Materials, 2023
The propagation of P-waves and S-waves has great relevance to those engaged in earthquake engineering research. The P-wave motion is same as that of sound wave in air, that is, it alternately pushes (compresses) and pulls (dilates) the structure. The motion of the particles is always in the direction of propagation. This wave, like sound, travels both in solids and fluids. It may be mentioned that, because of sound like nature, when P-wave emerges from deep in the Earth to the surface, a fraction of it is transmitted into atmosphere as sound waves. Such sounds, if frequency is greater than 15 cycles per second, are audible to animals or human beings. These are known as Earthquake Sound. The pictorially, the propagation of P-waves and S-waves is shown in Fig. 7.2.
Petroleum Seismological Survey
Published in Muhammad Abdul Quddus, Petroleum Science and Technology, 2021
Primary waves are also called ‘pressure waves’, ‘compressional waves’, ‘longitudinal waves’ or ‘P-waves’. The wave propagates through the medium (solid and fluids) by the pressure exerted by seismic wave energy. The pressure creates alternate compression (pushing inside) and expansion/rarefaction (pulling apart) strain in the medium in the longitudinal direction of wave propagation. The medium (rock and liquid) particle motion is an oscillation back and forth, along the direction of wave propagation. The P-waves are the most important and used for underground geological seismic studies. The seismic P-waves are faster than any other types of wave, appear earlier at the surface recording station and are easily identifiable.
Wave propagation effects induced by standard penetration tests
Published in A. Verruijt, F.L. Beringen, E.H. De Leeuw, Penetration Testing, 2021
Any dynamic disturbance created inside a soil mass generates stress waves that propagate, as dilatational P-waves and shear S-waves, from the point of disturbance through the soil. As the waves travel outward from the source, attenuation of stresses occur due to hysteretic damping, proper of the material, and to simple radiation or geometric damping. Performance of Standard Penetration Tests (SPT) genera tes such wave propagation effects, and, the refore, an SPT may be used to measure shear wave velocities and possibly other dynamic soil properties provided that adequate receiving stations are installed to record passage of the waves.
Effect of Soil Properties and Input Motion on Site Amplification Using Validated Nonlinear Soil Model
Published in Nuclear Technology, 2021
Samyog Shrestha, Efe G. Kurt, Kyungtae Kim, Arun Prakash, Ayhan Irfanoglu
When an earthquake occurs, compressional waves and shear waves, i.e., P-waves and S-waves, respectively, are generated that travel through the interior of the earth. P-waves cause particles to move parallel to the direction of wave propagation whereas S-waves cause shearing deformation as they travel through a material. The velocities at which these waves travel in different soil layers are required to model soil behavior under compression and shear loading. S-wave and P-wave velocity profiles and acceleration time series recorded during different earthquakes are available in the KiK-net database. Acceleration data are recorded by the strong motion accelerometers installed at the base of the borehole and at the ground surface of each station. Table I shows the sites and details of the input motions including date of earthquake, moment magnitude, epicentral distance, and peak surface acceleration considered for validation of the benchmark numerical soil column model in MASTODON. Figure 2 shows locations of the selected sites and epicenters of the earthquakes considered. Three-component ground motion recorded during the event dated 11/22/2016 for the Iwaki-E (FKSH14) downhole array site is shown in Fig. 3.
Using P-wave propagation velocity to characterize damage and estimate deformation modulus of in-situ rock mass
Published in European Journal of Environmental and Civil Engineering, 2022
As the value of the Poisson’s ratio reported for certain types of intact rocks varies slightly over a narrow interval (Gercek, 2007), the density and Poisson’s ratio in Equation (1) have been assumed to be constant in previous studies (Qiang et al., 2011; Yan & Xu, 2005). Evidently, for both intact rocks and rock mass, the relative differences in the density and Poisson’s ratio are generally significantly smaller than that of the P-wave propagation velocity. As a result, the damage variable of in-situ rock mass is fundamentally associated with changes in the P-wave propagation velocity before and after the occurrence of damage. However, if the influence of the density and Poisson’s ratio are completely ignored, this approach may be somewhat biased. Therefore, for intact rocks and rock mass with the same lithological properties, the differences in the densities and Poisson’s ratios between these two distinguished geological materials were set to a%–b% and 0–c%, respectively, i.e., ρ’ = [1−b%, 1−a%]ρ, μ’= [1, 1+c%]μ. In general, as the P-wave propagation velocity attenuates, the damage variable increases, and vice versa. For simplicity, it is imperative to eliminate the influence of the density and Poisson’s ratio on the dimensionless parameter, D, in Equation (1), in a reasonable and reliable way. Thus, that portion of Equation (1) is denoted by the symbol λ, and can be rewritten as with where
Magneto-thermo-elastic plane waves in a rotating micropolar fiber-reinforced solid/liquid media under G–L theory for non-insulated boundary: reflection and transmission
Published in Waves in Random and Complex Media, 2022
Augustine Igwebuike Anya, Adnan Jahangir, Aftab Khan
Seismic wave is categorized majorly in two forms; body wave and surface wave. The former travels through the body of the medium, for example, P and SV waves while the latter travels through the surface of the medium, e.g. Rayleigh, Love and Stoneley waves. Body waves make ray paths refracted by the variation of the ratio of its mass and volume along with the stiffness of the interior. P-waves are primary waves, which are compressional in nature and travel faster than any other form of waves. It usually travels through any type of material with twice the speed of secondary waves (SV-waves).