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湿热环境下嵌入黏弹性基础中的黏弹性磁致伸缩板的振动

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Acta mechanica Sinica 2023年第5期39卷 144-159页

作者： ashraf m.zenkour Hela D.El-Shahrany Department of mathematics Faculty of ScienceKing Abdulaziz UniversityJeddah21589Saudi Arabia Department of mathematics Faculty of ScienceKafrelsheikh UniversityKafrelsheikh33516Egypt Department of mathematics Faculty of ScienceUniversity of BishaBisha67714Saudi Arabia

本文研究了湿热荷载作用下自适应夹芯板在黏弹性介质中的振动.简单支撑的夹芯板包含三种类型的层:纤维增强层、两个磁致伸缩致动器和黏弹性面.结构的顶部和底部建模为Kelvin-Voigt黏弹性模型.基于板理论,主要振动模式应用汉密尔顿原理.... 详细信息

本文研究了湿热荷载作用下自适应夹芯板在黏弹性介质中的振动.简单支撑的夹芯板包含三种类型的层:纤维增强层、两个磁致伸缩致动器和黏弹性面.结构的顶部和底部建模为Kelvin-Voigt黏弹性模型.基于板理论,主要振动模式应用汉密尔顿原理.数值算例研究了各种参数对湿热振动特性的影响,如厚度比、长径比、黏弹性与磁致伸缩层厚度比、模态、黏弹性基体刚度和阻尼系数、层压方案、反馈系数大小、磁致伸缩层位置、黏弹性结构阻尼、温升和水分浓度的程度.研究结果表明温度和湿度浓度是影响振动的主要因素.对于在湿热荷载作用下板的设计,上述研究结果有助于智能结构的开发与应用并控制其在这种环境条件下的振动.

关键词： Vibration suppression Laminated composite plate magnetostrictive and viscoelastic materials Hygrothermal loads Visco-Pasternak’s foundations

The effect of fractional thermoelasticity on a two-dimensional problem of a mode I crack in a rotating fiber-reinforced thermoelastic medium

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Chinese Physics B 2013年第10期22卷 575-582页

作者： Ahmed E.Abouelregal ashraf m.zenkour Department of mathematics Faculty of ScienceMansoura University Department of mathematics Faculty of ScienceKing Abdulaziz University Department of mathematics College of Science and ArtsUniversity of Aljouf Department of mathematics Faculty of ScienceKafrelsheikh University

This article is concerned with the effect of rotation on the general model of the equations of the generalized thermoe- lasticity for a homogeneous isotropic elastic half-space solid, whose surface is subjected to a mode-I crack problem. The fractional order theory of thermoelasticity is used to obtain the analytical solutions for displacement components, force stresses, and temperature. The boundary of the crack is subjected to a prescribed stress distribution and temperature. The normal mode analysis technique is used to solve the resulting non-dimensional coupled governing equations of the problem. The variations of the considered variables with the horizontal distance are illustrated graphically. Some particular cases are also discussed in the context of the problem. Effects of the fractional parameter, reinforcement, and rotation on the varia- tions of different field quantities inside the elastic medium are analyzed graphically. Comparisons are made between the results in the presence and those in the absence of fiber-reinforcing, rotating and fractional parameters.

关键词： fiber-reinforced mode-I crack fractional order thermoelasticity theory rotating medium normalmode analysis

Thermoelastic diffusion problem for a half-space due to a refined dual-phase-lag Green-Naghdi model

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Journal of Ocean Engineering and Science 2020年第3期5卷 214-222页

作者： ashraf m.zenkour Department of mathematics Faculty of ScienceKing Abdulaziz UniversityP.O.Box 80203Jeddah 21589Saudi Arabia Department of mathematics Faculty of ScienceKafrelsheikh UniversityKafrelsheikh 33516Egypt

The thermoelastic diffusion problem of an isotropic half-space is *** Green-Naghdi model with and without energy dissipation is *** multi single/dual-phase-lag models are presented to investigate the thermoelastic diffusion behavior of the *** simple Green-Naghdi type Ⅱ and Ⅲ and their modified models are all examined *** exact solution of thermodiffusion governing equations has been obtained considering the initial and boundary *** validity of results is acceptable by comparing all *** results are reported to help other investigators in their future comparisons.

关键词： Green–NaghdiⅡ Ⅲ Thermodiffusion Chemical potential Dual-phase-lag

Thermodynamical Bending of FGm Sandwich Plates Resting on Pasternak’s Elastic Foundations

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Advances in Applied mathematics and mechanics 2015年第1期7卷 116-134页

作者： mohammed Sobhy ashraf m.zenkour Department of mathematics Faculty of ScienceKing Faisal UniversityP.O.Box 400Hufof 31982Saudi Arabia Department of mathematics Faculty of ScienceKing Abdulaziz UniversityP.O.Box 80203Jeddah 21589Saudi Arabia Department of mathematics Faculty of ScienceKafrelsheikh UniversityKafrelsheikh 33516Egypt

The analysis of thermoelastic deformations of a simply supported functionally graded material(FGm)sandwich plates subjected to a time harmonic sinusoidal temperature field on the top surface and varying through-the-thickness is illustrated in this *** FGm sandwich plates are assumed to be made of three layers and resting on Pasternak’s elastic *** volume fractions of the constituents of the upper and lower layers and,hence,the effective material properties of them are assumed to vary in the thickness direction only whereas the core layer is still *** in-plane sinusoidal variations of the displacements and the temperature that identically satisfy the boundary conditions at the edges,the governing equations of motion are solved analytically by using various shear deformation theories as well as the classical *** influences of the time parameter,power law index,temperature exponent,top-to-bottom surface temperature ratio,side-to-thickness ratio and the foundation parameters on the dynamic bending are investigated.

关键词： FGm sandwich plates dynamic bending elastic foundations thermal load

Transient analysis of a three-layer microbeam subjected to electric potential

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International Journal of Smart and Nano materials 2017年第1期8卷 20-40页

作者： mohammad Arefi ashraf m.zenkour Department of Solid mechanics Faculty of Mechanical EngineeringUniversity of KashanKashanIran Department of mathematics Faculty of ScienceKing Abdulaziz UniversityJeddahSaudi Arabia Department of mathematics Faculty of ScienceKafrelsheikh UniversityKafrelsheikhEgypt

In this paper,free vibration,wave propagation,and bending analyses of a sandwich microbeam integrated with piezoelectric face-sheets resting on Pasternak foundation under electric potential are presented based on the strain gradient theory and Euler–Bernoulli beam *** material properties of core are assumed variable along the thickness direction and piezoelectric face-sheets are assumed homogeneous piezoelectric materials.A two-dimensional electric potential distribution along the axial and transverse direction is applied on the face-sheets of *** principal is used to derive governing differential equations of *** behaviors of sandwich microbeam including free vibration,wave propagation,and bending analyses are studied in this *** numerical results are presented to capture the effect of important parameters of the problem such as in-homogeneous index,applied voltage,parameters of foundation,and material length *** numerical results indicate that the effect of electric potential along the axial direction is very small rather than one along the transverse direction where initial voltage is applied.

关键词： Euler–Bernoulli three-layer microbeam free vibration wave propagation electric potential applied voltage

On the Generalized Thermoelasticity Problem for an Infinite Fibre-Reinforced Thick Plate under Initial Stress

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Advances in Applied mathematics and mechanics 2014年第6期6卷 783-796页

作者： Ahmed E.Abouelregal ashraf m.zenkour Department of mathematics Faculty of ScienceMansoura UniversityMansoura 35516Egypt Department of mathematics Faculty of ScienceKing Abdulaziz UniversityP.O.Box 80203Jeddah 21589Saudi Arabia Department of mathematics College of Science and ArtsUniversity of AljoufEl-QurayatSaudi Arabia Department of mathematics Faculty of ScienceKafrelsheikh UniversityKafr El-Sheikh 33516Egypt

In this paper,the generalized thermoelasticity problem for an infinite fiberreinforced transversely-isotropic thick plate subjected to initial stress is *** lower surface of the plate rests on a rigid foundation and temperature while the upper surface is thermally insulated with prescribed surface *** normal mode analysis is used to obtain the analytical expressions for the displacements,stresses and temperature *** problem has been solved analytically using the generalized thermoelasticity theory of *** of phase-lags,reinforcement and initial stress on the field quantities is shown *** results due to the coupled thermoelasticity theory,Lord and Shulman’s theory,and Green and Naghdi’s theory have been derived as limiting *** graphs illustrated that the initial stress,the reinforcement and phase-lags have great effects on the distributions of the field quantities.

关键词： Dual-phase-lag theory fiber-reinforced initial stress normal mode analysis thick plate.

Bending of orthotropic plates resting on Pasternak's foundations using mixed shear deformation theory

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Acta mechanica Sinica 2011年第6期27卷 956-962页

作者： A.m.zenkour Department of mathematics Faculty of Science King AbdulAziz University Department of mathematics Faculty of Science Kafrelsheikh University

The mixed first-order shear deformation plate theory（mFPT） is employed to study the bending response of simply-supported orthotropic *** present plate is subjected to a mechanical load and resting on Pasternak＇s model or Winkler＇s model of elastic foundation or without any elastic *** examples are presented to verify the accuracy of the present *** results for deflection and stresses are *** proposed mFPT is shown simplely to implement and capable of giving satisfactory results for shear deformable plates under static loads and resting on two-parameter elastic *** results presented here show that the characteristics of deflection and stresses are significantly influenced by the elastic foundation stiffness,plate aspect ratio and side-to-thickness ratio.

关键词： mixed theory Bending Rectangular plates Pasternak's model

Stresses in rotating heterogeneous viscoelastic composite cylinders with variable thickness

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Applied mathematics and mechanics(English Edition) 2011年第4期32卷 507-520页

作者： A.m.zenkour Department of mathematics Faculty of ScienceKing AbdulAziz University Department of mathematics Faculty of ScienceKafrelsheikh University

An analytical solution is presented for the rotation problem of a two-layer composite elastic cylinder under a plane strain assumption. The external cylinder has variable-thickness formulation, and is made of a heterogeneous orthotropic material. It contains a fiber-reinforced viscoelastic homogeneous isotropic solid core of uniform thickness. The thickness and elastic properties of the external cylinder are taken as power functions of the radial direction. By the boundary and continuity conditions, the radial displacement and stresses for the rotating composite cylinder are determined. The effective moduli and Illyushin＇s approximation methods are used to obtain the viscoelastic solution to the problem. The effects of heterogeneity, thickness variation, constitutive, time parameters on the radial displacement, and stresses are investigated.

关键词： rotating composite cylinder orthotropic heterogeneous variable-thickness fiber-reinforced viscoelastic core

BENDING RESPONSES OF AN EXPONENTIALLY GRADED SImPLY-SUPPORTED ELASTIC/VISCOELASTIC/ELASTIC SANDWICH PLATE

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Acta mechanica Solida Sinica 2011年第3期24卷 250-261页

作者： A.m.zenkour Department of mathematics Faculty of ScienceKing AbdulAziz University Department of mathematics Faculty of ScienceKafr El-Sheikh University

The bending response for exponentially graded composite （EGC） sandwich plates is investigated. The three-layer elastic/viscoelastic/elastic sandwich plate is studied by using the sinusoidal shear deformation plate theory as well as other familiar theories. Four types of sand- wich plates are considered taking into account the symmetry of the plate and the thickness of each layer. The effective moduli and Illyushin＇s approximation methods are used to solve the equations governing the bending of simply-supported EGC fiber-reinforced viscoelastic sandwich plates. Then numerical results for deflections and stresses are presented and the effects due to time parameter, aspect ratio, side-to-thickness ratio and constitutive parameter are investigated.

关键词： symmetric sandwich plates viscoelasticity EGC sinusoidal plate theory