scholarly journals Dynamic Responses of a Multilayered Transversely Isotropic Poroelastic Seabed Subjected to Ocean Waves and Currents

2022 ◽  
Vol 10 (1) ◽  
pp. 73
Author(s):  
Xi Chen ◽  
Qi Zhang ◽  
Xiang Yuan Zheng ◽  
Yu Lei
Keyword(s):  
Young’S Modulus ◽  
Young's Modulus ◽  
Dynamic Stiffness ◽  
Transversely Isotropic ◽  
Ocean Waves ◽  
Offshore Structures ◽  
Dynamic Responses ◽  
Vertical Shear ◽  
Waves And Currents ◽  
Poroelastic Seabed

In this study, a semi-analytical solution to the dynamic responses of a multilayered transversely isotropic poroelastic seabed under combined wave and current loadings is proposed based on the dynamic stiffness matrix method. This solution is first analytically validated with a single-layered and a two-layered isotropic seabed and then verified against previous experimental results. After that, parametric studies are carried out to probe the effects of the soil’s anisotropic characteristics and the effects of ocean waves and currents on the dynamic responses and the maximum liquefaction depth. The results show that the dynamic responses of a transversely isotropic seabed are more sensitive to the ratio of the soil’s vertical Young’s modulus to horizontal Young’s modulus (Ev/Eh) and the ratio of the vertical shear modulus to Ev (Gv/Ev) than to the vertical-to-horizontal ratio of the permeability coefficient (Kv/Kh). A lower degree of quasi-saturation, higher porosity, a shorter wave period, and a following current all result in a greater maximum liquefaction depth. Moreover, it is revealed that the maximum liquefaction depth of a transversely isotropic seabed would be underestimated under the isotropic assumption. Furthermore, unlike the behavior of an isotropic seabed, the transversely isotropic seabed tends to liquefy when fully saturated in nonlinear waves. This result supplements and reinforces the conclusions determined in previous studies. This work affirms that it is necessary for offshore engineering to consider the transversely isotropic characteristics of the seabed for bottom-fixed and subsea offshore structures.

scholarly journals Seepage Force on a Buried Submarine Pipeline Induced by a Solitary Wave

2020 ◽  
Vol 8 (5) ◽  
pp. 324
Author(s):  
Meng-Yu Lin ◽  
Li-Jie Wang
Keyword(s):  
Solitary Wave ◽  
Young’S Modulus ◽  
Permeability Coefficient ◽  
Pore Water Pressure ◽  
Young's Modulus ◽  
Water Pressure ◽  
Vertical Force ◽  
Submarine Pipeline ◽  
Seepage Force ◽  
Poroelastic Seabed

In this study, a finite element method was used to establish a two-dimensional numerical model to solve the problem of the Biot equation describing the poroelastic seabed, and to analyze the seepage force on a buried submarine pipeline under the propagation of a solitary wave. The model provides a solution to the displacement of the poroelastic seabed and the variation of the pore-water pressure. By means of numerical simulation, the effects of Young’s modulus and permeability coefficient of the soil on the pore-water pressure and seepage force are discussed. In the simulation of solitary waves passing through fully buried submarine pipelines, numerical results indicate that the smaller the permeability coefficient in dense sandy bed the greater the vertical force acting on the pipeline, and the smaller the permeability coefficient in loose sand bed the smaller the vertical force acting on the pipeline. In general, when the permeability coefficient is large, the smaller the Young’s modulus the more obvious the influence of the vertical force on the pipeline, and when the permeability coefficient is small, the larger the Young’s modulus the more obvious the influence of the vertical force on the pipeline.

Dynamic Responses of Plates With Viscoelastic Free Layer Damping Treatment

1996 ◽  
Vol 118 (3) ◽  
pp. 362-367 ◽  
Author(s):  
Sung Yi ◽  
M. Fouad Ahmad ◽  
H. H. Hilton
Keyword(s):  
Young’S Modulus ◽  
Layer Thickness ◽  
Young's Modulus ◽  
Dynamic Responses ◽  
Viscoelastic Damping ◽  
Free Layer ◽  
Modulus Ratio ◽  
Transient Responses ◽  
Damping Materials

Dynamic transient responses of plates with viscoelastic free damping layers are studied in order to evaluate free layer damping treatment performances. The effects of forcing frequencies and temperatures on free-layer viscoelastic damping treatment of plates are investigated analytically. Young’s modulus ratio of structures to viscoelastic damping materials and the damping layer thickness effects on the damping ability are also explored.

Elastic, Transversely Isotropic Film Indented by a Punch; Application to Multilayered Thin Films

1994 ◽  
Vol 356 ◽  
Author(s):  
D.S. Stone
Keyword(s):  
Thin Films ◽  
Data Analysis ◽  
Amorphous Silicon ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Transversely Isotropic ◽  
Elastic Contact ◽  
Multilayer Composites ◽  
Multilayered Thin Films

AbstractA model calculates the compliance of elastic contact between a punch and bilayer, the latter consisting of a transversely isotropic film on top of isotropic substrate. Used in data analysis, the model helps estimate the Young’s modulus of amorphous silicon (100±20 GPa) layers within amorphous silicon/aluminum multilayer composites deposited on silicon.

scholarly journals Development of an improved mathematical model for the dynamic response of a sphere located at a viscoelastic medium interface

2021 ◽  
Author(s):  
Hasan Koruk
Keyword(s):  
Mathematical Model ◽  
Dynamic Response ◽  
Elastic Medium ◽  
Young’S Modulus ◽  
Viscoelastic Medium ◽  
Young's Modulus ◽  
Radiation Damping ◽  
Dynamic Responses ◽  
Static Displacement ◽  
Medium Interface

Abstract A comprehensive investigation on the static and dynamic responses of a sphere located at elastic and viscoelastic medium interfaces is performed in this study. First, the mathematical models commonly used for predicting the static displacement of a sphere located at an elastic medium interface are presented and their performances are compared. After that, based on the finite element analyses, an accurate mathematical model to predict the static displacement of a sphere located at an elastic medium interface valid for different Poisson’s ratios of the medium and small and large sphere displacements is proposed. Then, an improved mathematical model for the dynamic response of a sphere located at a viscoelastic medium interface is developed. In addition to the Young’s modulus of the medium and the radius of the sphere, the model takes into account the density, Poisson’s ratio and viscosity of the medium, the mass of the sphere and the radiation damping. The effects of the radiation damping, the Young’s modulus, density and viscosity of the medium and the density of the sphere on the dynamic response of the sphere located at a viscoelastic medium interface are explored. The developed model can be used to understand the dynamic responses of spherical objects located at viscoelastic medium interfaces in practical applications. Furthermore, the proposed model is a significant tool for graduate students and researchers in the fields of engineering, materials science and physics to gain insight into the dynamic responses of spheres located at viscoelastic medium interfaces.

Dynamic Responses of Plates With Viscoelastic Damping Treatment

1993 ◽  
Author(s):  
Sung Yi ◽  
M. Fouad Ahmad ◽  
Harry H. Hilton
Keyword(s):  
Young’S Modulus ◽  
Layer Thickness ◽  
Young's Modulus ◽  
Dynamic Responses ◽  
Viscoelastic Damping ◽  
Free Layer ◽  
Modulus Ratio ◽  
Transient Responses ◽  
Damping Materials

Abstract Dynamic transient responses of plates with free damping layers are studied in order to evaluate free layer damping treatment performances. The effects of forcing frequencies and temperatures on free-layer viscoelastic damping treatment of plates are investigated analytically. Young’s modulus ratio of structures to viscoelastic damping materials and the damping layer thickness effects on the damping ability are also explored.

scholarly journals Effect of the Confining Pressure on the Dynamic Compression Properties of Transversely Isotropic Rocks

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Xuefeng Ou ◽  
Xuemin Zhang ◽  
Han Feng ◽  
Cong Zhang ◽  
Junsheng Yang
Keyword(s):  
Young’S Modulus ◽  
Split Hopkinson Pressure Bar ◽  
Young's Modulus ◽  
Dynamic Compression ◽  
Dynamic Strength ◽  
Transversely Isotropic ◽  
Confining Pressure ◽  
Bedding Plane ◽  
Hopkinson Pressure Bar ◽  
Compression Properties

The dynamic compression properties of transversely isotropic rocks and their dependence on the confining pressure and bedding directivity are important in deep underground engineering activities. In this study, a slate is characterized using a split Hopkinson pressure bar (SHPB) test. Five groups of samples with preferred bedding directions (dip angles of 0°, 30°, 45°, 60°, and 90°) are subjected to coupled axial impact loading (low, medium, and high) under confining pressure (0, 5, and 10 MPa). The failure mode, dynamic strength, and Young’s modulus are investigated. The test results show that the tensile splitting effect is significant when there is no confining pressure. However, under a confining pressure (5 and 10 MPa) condition, the cracks that develop along the loading direction can be significantly constrained and the samples are forced to fail along the bedding plane. With increasing confining pressure, the critical dynamic strength significantly increases, and Young’s modulus increases when θ≥45° while it decreases when θ≤30°.

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