scholarly journals Research on coupled thermo-hydro-mechanical dynamic response characteristics of saturated porous deep-sea sediments under vibration of mining vehicle

2021 ◽  
Author(s):  
Wei Zhu ◽  
Xinyu Shi ◽  
Rong Huang ◽  
Liyue Huang ◽  
Wenbo Ma
Keyword(s):  
Deep Sea ◽  
Volume Fraction ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Normal Mode Analysis ◽  
Vertical Displacement ◽  
Mode Analysis ◽  
Analysis Method ◽  
Deep Sea Sediments ◽  
Physical Quantities

AbstractThe excessive deformation of deep-sea sediments caused by the vibration of the mining machine will adversely affect the efficiency and safety of mining. Combined with the deep-sea environment, the coupled thermo-hydro-mechanical problem for saturated porous deep-sea sediments subject to the vibration of the mining vehicle is investigated. Based on the Green-Lindsay (G-L) generalized thermoelastic theory and Darcy’s law, the model of thermo-hydro-mechanical dynamic responses for saturated porous deep-sea sediments under the vibration of the mining vehicle is established. We obtain the analytical solutions of non-dimensional vertical displacement, excess pore water pressure, vertical stress, temperature, and change in the volume fraction field with the normal mode analysis method, and depict them graphically. The normal mode analysis method uses the canonical coordinate transformation to solve the equation, which can quickly decouple the equation by ignoring the modal coupling effect on the basis of the canonical mode. The results indicate that the vibration frequency has obvious influence on the vertical displacement, excess pore water pressure, vertical stress, and change in volume fraction field. The loading amplitude has a great effect on the physical quantities in the foundation, and the changes of the physical quantities increase with the increase in loading amplitude.

Influence of gravity and micro-temperatures on the thermoelastic porous medium under three theories

2019 ◽  
Vol 29 (9) ◽  
pp. 3242-3262 ◽  
Author(s):  
Mohamed I.A. Othman ◽  
Elsayed M. Abd-Elaziz
Keyword(s):  
Design Methodology ◽  
Volume Fraction ◽  
Normal Mode Analysis ◽  
Mode Analysis ◽  
Field Equations ◽  
Content Type ◽  
Thermoelastic Solid ◽  
Lord And Shulman Theory ◽  
Physical Quantities ◽  
Coupled Theory

Purpose The purpose of this study is to obtain a general solution to the field equations of thermoelastic solid with voids and micro-temperatures under the gravitational field in the context of the three theories, namely, coupled theory (CT), Lord and Shulman theory and Green and Lindsay theory. Design/methodology/approach The normal mode analysis is used to obtain the exact expressions for the considered variables. Comparisons are made with the results obtained in the three theories with and without gravity. Some particular cases are also deduced from the present investigation. Findings The effect of the gravity on the displacement, the micro-temperature vector, the temperature distribution, the normal stress, the changes in the volume fraction field and the heat flux moments have been depicted graphically. Research limitations/implications Some particular cases are also deduced from the present investigation. Originality/value The results of the physical quantities have been illustrated graphically by a comparison between three different theories in the presence and absence of gravity.

Effect of magnetic field on a rotating thermoelastic medium with voids under thermal loading due to laser pulse with energy dissipation

2014 ◽  
Vol 92 (11) ◽  
pp. 1359-1371 ◽  
Author(s):  
Mohamed I.A. Othman ◽  
Magda E.M. Zidan ◽  
Mohamed I.M. Hilal
Keyword(s):  
Magnetic Field ◽  
Laser Pulse ◽  
Thermal Loading ◽  
Volume Fraction ◽  
Plane Surface ◽  
Normal Mode Analysis ◽  
Mode Analysis ◽  
Gaussian Laser Beam ◽  
Thermoelastic Solid ◽  
Non Gaussian

This investigation deals with the rotation of magneto-thermoelastic solid with voids subjected to thermal loading due to laser pulse. The bounding plane surface is heated by a non-Gaussian laser beam. The entire porous medium is rotated with a uniform angular velocity. The problem is studied in the context of Green–Naghdi (GN) theory of types II and III, with the effect of rotation, magnetic field, thermal loading and voids. Normal mode analysis is used to solve the physical problem to obtain the exact expressions for the displacement components, stresses, temperature distribution, and change in the volume fraction field, which have been shown graphically by comparison between two types of GN theory (types II and III) in the presence and the absence of rotation and magnetic field and for two values of time on thermoelastic material with voids.

Effect of initial stress and rotation on magneto-thermoelastic material with voids and energy dissipation

2017 ◽  
Vol 13 (2) ◽  
pp. 331-346 ◽  
Author(s):  
Mohamed Ibrahim A. Othman ◽  
Mohamed Ibrahim M. Hilal
Keyword(s):  
Laser Pulse ◽  
Initial Stress ◽  
Pulse Heating ◽  
Normal Mode Analysis ◽  
Mode Analysis ◽  
Content Type ◽  
Thermoelastic Material ◽  
Analysis Technique ◽  
Laser Pulse Heating ◽  
Physical Quantities

Purpose The purpose of this paper is to study the effect of rotation and initial stress on magneto-thermoelastic material with voids heated by a laser pulse heating. Design/methodology/approach The analytical method used was the normal mode analysis technique. Findings Numerical results for the physical quantities were presented graphically and analyzed. The graphical results indicate that the effect of rotation, initial stress and magnetic fields are observable physical effects on the thermoelastic material with voids heated by a laser pulse. Comparisons are made with the results in the absence and the presence of the physical operators, also at various times. Originality/value In the present work, the authors shall investigate the effect of the rotation, initial stress, magnetic field and laser pulse on thermoelastic material with voids subjected to a laser pulse heating acting as a thermal shock. A comparison is also made between the two types (types II and III) of Green-Naghdi theory in the absence and the presence of the physical operators. Such problems are very important in many dynamical systems.

scholarly journals Initial Hypotheses for Modeling and Numerical Analysis of Rockfill and Earth Dams and Their Effects on the Results of the Analysis

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Mohammad Rashidi ◽  
Habib Rasouli
Keyword(s):  
Bulk Modulus ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Numerical Analyses ◽  
Earth Dams ◽  
Analysis Method ◽  
Replacement Method ◽  
Behavioral Parameters ◽  
High Dams ◽  
Parametric Analyses

Since the behavior of earth dams is unreliable in different stages of construction, impounding, and exploitation, this matter is an unavoidable and essential issue with regard to the serious dangers caused by the failure of these important structures. It is crucial to evaluate the behavior of dams and examine the consistency between the carried out analyses and the behavioral parameters under different conditions in the lifespan of dams due to the uncertainty of the principles and hypotheses which have been adopted to analyze these structures. This objective will be accomplished through the help of correct numerical analyses. A series of hypotheses are adopted to simplify the parametric analyses before starting these analyses. The aim of this research is to develop and discuss these hypotheses. And so, the number of elements and their effects on the results of analyses were examined through the consolidation of unsaturated soil method, the compressible fluid method, correlated analysis, and uncorrelated analysis. It became clear after the numerical analyses that correlated analysis is a more precise method in comparison with the uncorrelated analysis method. However, this method is not economical when it comes to high dams and the replacement method is the uncorrelated analysis. Furthermore, the displacements are not that sensitive to the bulk modulus of water while the maximum settlement of the dam transfers from the middle of the dam’s core to a location higher than that the core as the bulk modulus of water increases. However, pore water pressure is very sensitive to the bulk modulus of water.

Analysis on Vibrations due to High-Speed Railway Tunnel and Control Measures

2012 ◽  
Vol 226-228 ◽  
pp. 381-386
Author(s):  
Xiao Juan Quan ◽  
Kai Shi ◽  
Yi Bo Yan
Keyword(s):  
Pore Water ◽  
High Speed ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Vertical Displacement ◽  
Normal Operation ◽  
Shield Tunnel ◽  
Tunnel Structure ◽  
High Speed Railway ◽  
Grouting Reinforcement

With the economy developing rapidly, China has entered the era of high-speed railway, but at the same time, the negative impact of high-speed railway is increasing obviously. The paper analyzes the induced environmental vibration problems due to the high-speed railway, the specific response in the power of the shield tunnel under the train loads, the tunnel structure and the surrounding strata, When the local layer is saturated sand, by calculating the pore water pressure and the layer stress, determining whether it can cause sand liquefaction phenomenon or not, judging the damage extent of tunnel structure, especially it may influences the normal operation of the train. The vertical displacement of the tunnel structure due to the dynamic train load may have impact on the normal operation of the train, where some preventive measures should be taken, such as concrete grouting reinforcement method. In this paper the non-reinforcement case is compared to the reinforcing ones, and different reinforcement ring thickness is studied in order to determine a reasonable thickness of the reinforcement. The main contents include the following work: （1）Response analysis by using the FLAC3D software to simulate the shield tunnel under the dynamic train loads which are the main cause of the displacement of the segment and surrounding strata. The simulation study mainly includes analysis of the changes of pore water pressure and stress. （2） Since train load can produce the vertical displacement, prevention and controlling measures should be taken, which mainly use grouting reinforcement.

Effect of Magnetic Field on Generalized Thermo-Viscoelastic Diffusion Medium with Voids

2016 ◽  
Vol 16 (07) ◽  
pp. 1550033 ◽  
Author(s):  
Mohamed I. A. Othman ◽  
Montaser Fekry
Keyword(s):  
Magnetic Field ◽  
Normal Mode Analysis ◽  
Generalized Thermoelasticity ◽  
Mode Analysis ◽  
Physical Domain ◽  
Specific Material ◽  
Analytical Expressions ◽  
And Diffusion ◽  
Physical Quantities ◽  
The Magnetic Field

The present paper is concerned with the investigation of disturbances in a homogeneous, isotropic, generalized thermo-viscoelastic diffusion material with voids under the influence of magnetic field. The formulation is applied to the generalized thermoelasticity theory under the Lord–Shulman and the classical dynamical coupled theories. The analytical expressions for the physical quantities are obtained in the physical domain by using the normal mode analysis. These expressions are calculated numerically for a specific material and explained graphically. Comparisons are made with the results predicted by the Lord–Shulman and the coupled theories in the presence and absence of the magnetic field and diffusion.

scholarly journals Normal Mode Analysis of Generalized Magneto-Thermoelastic Medium with Initial Stress Under Green-Naghdi Theory

2020 ◽  
Vol 35 (4) ◽  
pp. 313-325
Author(s):  
Alzaerah Ramadhan Mohammed Aldeeb
Keyword(s):  
Magnetic Field ◽  
Initial Stress ◽  
Normal Mode ◽  
Normal Mode Analysis ◽  
Mode Analysis ◽  
Energy Dispersion ◽  
Elasticity Equations ◽  
Physical Quantities ◽  
The Magnetic Field ◽  
Research Show

The normal mode analysis method was used to study the effect of both the initial stress and the magnetic field on a thermally elastic body. This method is used to obtain the exact expressions for the considered variables. Some particular cases are also discussed in the context of the problem. The generalized thermal elasticity equations were reviewed under the influence of the basic initial stress and the magnetic field using the theory (Green-Naghdi) of the second and third types (the second type with no energy dispersion and the third type with energy dispersion). The different physical quantities were illustrated in the presence and absence of both the initial stress and the magnetic field. The results of this research show the extent of difference between the second and third types of Green and Naghdi's theory. All results and figures were obtained using (MATLAB R2013a) program

Effect of rotation and gravity on generalized thermo-viscoelastic medium with voids

2018 ◽  
Vol 14 (2) ◽  
pp. 322-338 ◽  
Author(s):  
Mohamed I.A. Othman ◽  
Montaser Fekry
Keyword(s):  
Viscoelastic Material ◽  
Viscoelastic Medium ◽  
Normal Mode Analysis ◽  
Relaxation Times ◽  
Mode Analysis ◽  
Content Type ◽  
Analysis Technique ◽  
Effects Of Rotation ◽  
Physical Quantities ◽  
Coupled Theory

PurposeThe purpose of this paper is to study the effect of rotation and gravity on a homogeneous, isotropic, and generalized thermo-viscoelastic material with voids. The problem is studied in the context of the coupled theory, Lord-Shulman theory with one relaxation time, and Green-Lindsay theory with two relaxation times.Design/methodology/approachThe analytical method used was the normal mode analysis technique.FindingsNumerical results for the physical quantities were analyzed and presented graphically. The graphical results indicated that the effects of rotation and gravity were observable physical effects on the thermo-viscoelastic material with voids. Comparisons were made between the results obtained in the absence and presence of rotation and gravity.Originality/valueIn the present work, the authors investigated the effect of rotation and gravity on thermo-viscoelastic medium with voids. Comparisons were also made between the three theories in the absence and the presence of rotation and gravity. Such problems are very important in many dynamical systems.

scholarly journals Hydromagnetic thermal instability of compressible Walters’ (Model B′) rotating fluid permeated with suspended particles in porous medium

2013 ◽  
Vol 35 (4) ◽  
pp. 75-88
Author(s):  
G.C. Rana ◽  
H.S. Jamwal
Keyword(s):  
Magnetic Field ◽  
Porous Medium ◽  
Thermal Instability ◽  
Normal Mode Analysis ◽  
Suspended Particles ◽  
Mode Analysis ◽  
Analysis Method ◽  
Rotating Fluid ◽  
Medium Permeability ◽  
The Magnetic Field

Abstract In this paper, the thermal instability of compressible Walters’ (Model B′) rotating fluid permeated with suspended particles (fine dust) in porous medium in hydromagnetics is considered. By applying normal mode analysis method, the dispersion relation has been derived and solved analytically. It is observed that the rotation, magnetic field, suspended particles and viscoelasticity introduce oscillatory modes. For stationary convection, Walters’ (Model B′) elastico-viscous fluid behaves like an ordinary Newtonian fluid and it is observed that rotation has stabilizing effect, suspended particles are found to have destabilizing effect on the system, whereas the medium permeability has stabilizing or destabilizing effect on the system under certain conditions. The magnetic field has destabilizing effect in the absence of rotation, whereas in the presence of rotation, magnetic field has stabilizing or destabilizing effect under certain conditions

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