• Title/Summary/Keyword: thermoelastic analysis

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Frictionally Excited Thermoelastoplastic instability in sliding contact system (미끄러짐 마찰 접촉하는 시스템에서의 열탄소성 불안정성 연구)

  • Ahn, Seong-Ho;Jang, Yong-Hoon
    • Proceedings of the KSME Conference
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    • 2008.11a
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    • pp.144-149
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    • 2008
  • A transient finite element simulation is developed for the two-dimensional stationary elastoplastic layer between sliding layers, to investigate thermoelastoplastic instability(TEPI) due to frictional heating in the material. The analysis will show some differences between the case of thermoelastic instability and TEPI, especially according to the contact pressure above yield stress. A transient behavior of contact pressure is captured to explain the behavior of thermoplasticity of contact with different sliding velocity. The instability of contact pressure in the long range of braking time will be explored to understand the generation mechanism of hot spots.

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Dual-phase-lag model on microstretch thermoelastic medium with diffusion under the influence of gravity and laser pulse

  • Othman, Mohamed I.A.;Abd-Elaziz, Elsayed M.;Mohamed, Ibrahim E.A.
    • Structural Engineering and Mechanics
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    • v.75 no.2
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    • pp.133-144
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    • 2020
  • This investigation is to study the effect of gravitational field and diffusion on a microstretch thermoelastic medium heating by a non-Gaussian laser beam. The problem was studied in the context of the dual-phase-lag model. The normal mode analysis is used to solve the problem to obtain the exact expressions for the non-dimensional displacement components, the micro-rotation, the stresses, and the temperature distribution. The effect of time parameter, heat flux parameter and gravity response of three theories of thermoelasticity i.e. dual-phase-lag model (DPL), Lord and Shulman theory (L-S) and coupled theory (CT) on these quantities have been depicted graphically for a particular model.

2 D Computer Simulation of Laser-Generated Ultrasonic Wave (레이저 여기 초음파의 2차원 컴퓨터 시뮬레이션)

  • Kim, Gyeong-Jo
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.24 no.7 s.178
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    • pp.1847-1853
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    • 2000
  • A computer simulation technique for 2-dimensional laser generated ultrasonic waves was developed for visualization and investigation of ultrasonic propagation in solids. The technique is similar to a finite difference method (FDM) and a mass-particle model method, but uses a new nodal calculation method based on fundamental consideration of an elastic wave equation. By this method, the propagation behavior oflaser generated ultrasonic wave in thermoelastic and ablation mode is visualized and shows good agreement with previous experimental result or the numerical analysis result by Green function.

Wave propagation in a two-temperature fiber-reinforced magneto-thermoelastic medium with three-phase-lag model

  • Said, Samia M.;Othman, Mohamed I.A.
    • Structural Engineering and Mechanics
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    • v.57 no.2
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    • pp.201-220
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    • 2016
  • A general model of equations of the two-temperature theory of generalized thermoelasticity is applied to study the wave propagation in a fiber-reinforced magneto-thermoelastic medium in the context of the three-phase-lag model and Green-Naghdi theory without energy dissipation. The material is a homogeneous isotropic elastic half-space. The exact expression of the displacement components, force stresses, thermodynamic temperature and conductive temperature is obtained by using normal mode analysis. The variations of the considered variables with the horizontal distance are illustrated graphically. Comparisons are made with the results of the two theories in the absence and presence of a magnetic field as well as a two-temperature parameter. A comparison is also made between the results of the two theories in the absence and presence of reinforcement.

Spectral Element Analysis of an Axially Moving Thermoelastic Beam (축 방향으로 이동하는 열 탄성 보의 스펙트럴요소해석)

  • 김도연;권경수;이우식
    • Journal of the Korean Society for Railway
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    • v.7 no.3
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    • pp.239-244
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    • 2004
  • The use of frequency-dependent spectral element matrix (or exact dynamic stiffness matrix) in structural dynamics may provide very accurate solutions, together with drastically reducing the number of degrees of freedom to improve the computation efficiency and cost problems. Thus, this paper develops a spectral element model for the coupled thermoelastic beam which axially moves with constant speed under a uniform tension. The accuracy of the spectral element model is then evaluated by comparing the natural frequencies obtained by the present element model with those obtained by the conventional finite element model.

The effect of multi-phase-lag and Coriolis acceleration on a fiber-reinforced isotropic thermoelastic medium

  • Alharbi, Amnah M.;Said, Samia M.;Othman, Mohamed I.A.
    • Steel and Composite Structures
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    • v.39 no.2
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    • pp.125-134
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    • 2021
  • The three-phase-lag model, thermoelasticity without energy dissipation (G-N II) theory and thermoelasticity with energy dissipation (G-N III) theory are applied to study the effect of rotation on a fiber-reinforced thermoelastic medium. The exact expressions for the physical quantities were obtained by using the normal mode analysis. The numerical results for the field quantities are given in the physical domain and illustrated graphically in the absence and presence of rotation, Coriolis acceleration as well as reinforcement parameters.

Three-phase-lag model on a micropolar magneto-thermoelastic medium with voids

  • Alharbi, Amnah M.;Othman, Mohamed I.A.;Al-Autabi, Al-Anoud M. Kh.
    • Structural Engineering and Mechanics
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    • v.78 no.2
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    • pp.187-197
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    • 2021
  • This paper harnesses a micropolar thermoelastic medium consisting of voids to scrutinize the impacts of a magnetic field on it. To assess the problem, the three-phase-lag model (3PHL) has been employed and the analytical expressions of various variables under consideration have been derived using normal model analysis. The paper presents a graphical illustration of the material's stress, temperature, and dimensionless displacement. It has also been ensured that the predictions associated with results by different theories are not neglected instead; they are used to carry out appropriate comparisons in scenarios where the magnetic field is present as well as absent. The numerical results indicate that the magnetic field and the phase-lag of heat flux play a vital role in determining the distribution of field quantities. Thus, the investigation helped derive various interesting cases.

Effect of gravity on a micropolar thermoelastic medium with voids under three-phase-lag model

  • Alharbi, Amnah M.;Othman, Mohamed I.A.;Al-Autabi, Al-Anoud M.Kh.
    • Structural Engineering and Mechanics
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    • v.76 no.5
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    • pp.579-590
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    • 2020
  • This paper's objective is to investigate the effect of gravity on a micropolar thermoelastic medium with voids. The problem is assessed according to the three-phase-lag model. An analysis of the resulting non-dimensional displacement, temperature variation, and internal stress of the study material is carried out and presented graphically. The non-dimensional displacement, temperature, micro-rotation, the change in the volume fraction field and stress of the material are obtained and illustrated graphically. Comparisons are made with the results predicted by different theories for different values of gravity, the phase-lag of the heat flux and the phase-lag of the temperature gradient. The numerical results reveal that gravity and relaxation times have a significant influence on the distribution of the field quantities. Some notable insights of interest are deduced from the investigation.

A novel model of a rotating nonlocal micropolar thermoelastic medium with temperature-dependent properties

  • Samia M. Said;Elsayed M. Abd-Elaziz;Mohamed I.A. Othman
    • Structural Engineering and Mechanics
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    • v.90 no.4
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    • pp.429-434
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    • 2024
  • In the current work, the effect of rotation and mechanical force on a nonlocal micropolar thermoelastic solid with temperature-dependent properties was discussed using Erigen's nonlocal thermoelasticity theory. The problem is resolved using Laplace transforms and Fourier series. For the nonlocal and local parameters, the physical fields have been illustrated. The numerical inversion approach is used to acquire the resulting fields in the physical domain. Based on numerical analysis, the effects of rotation, the modulus of elasticity's dependency on temperature, and nonlocal, mechanical force are examined on the physical fields.

Effect of the gravity on a nonlocal thermoelastic medium with a heat source using fractional derivative

  • Samia M. Said
    • Geomechanics and Engineering
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    • v.37 no.6
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    • pp.591-597
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    • 2024
  • The purpose of this paper is to depict the effect of gravity on a nonlocal thermoelastic medium with initial stress. The Lord-Shulman and Green-Lindsay theories with fractional derivative order serve as the foundation for the formulation of the fundamental equations for the problem. To address the problem and acquire the exact expressions of physical fields, appropriate non-dimensional variables and normal mode analysis are used. MATLAB software is used for numerical calculations. The projected outcomes in the presence and absence of the gravitational field, along with a nonlocal parameter, are compared. Additional comparisons are made for various fractional derivative order values. It is evident that the variation of physical variables is significantly influenced by the fractional derivative order, nonlocal parameter and gravity field.