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M Mohammadimehr - One of the best experts on this subject based on the ideXlab platform.

  • surface stress and agglomeration effects on nonlocal biaxial Buckling polymeric nanocomposite plate reinforced by cnt using various approaches
    Advanced Composite Materials, 2016
    Co-Authors: Ghorbanpour A Arani, Rousta B Navi, M Mohammadimehr
    Abstract:

    In this article, the surface stress effect on the biaxial Critical Buckling Load of nonlocal polymeric nanocomposite rectangular plate reinforced by carbon nanotubes (CNTs) is presented. Various approaches such as Eshelby–Mori–Tanaka, the extended mixture rule, Halpin–Tsai, and micromechanical are used to determine the effective material properties of polymeric nanocomposite plate. The governing equations of equilibrium are obtained by using Hamilton’s principle. The Navier’s method is considered to obtain the biaxial Critical Buckling Load of polymeric nanocomposite rectangular plate for simply supported boundary conditions. A detailed parametric study is conducted to explain the effects of aspect ratio, elastic foundation, surface stress and agglomeration on the biaxial Buckling of nanocomposite plate. The results show that surface stress effect plays an important role at nanoscale. Also, the biaxial Critical Buckling Load decreases with increasing the CNTs volume fraction in the inclusion (agglomeratio...

  • bending Buckling and free vibration analysis of msgt microcomposite reddy plate reinforced by fg swcnts with temperature dependent material properties under hydro thermo mechanical Loadings using dqm
    Composite Structures, 2016
    Co-Authors: M Mohammadimehr, M Salemi, Rousta B Navi
    Abstract:

    Abstract In this paper, using third-order shear deformation theory (TSDT) and modified strain gradient theory (MSGT), bending, Buckling and free vibration behaviors of microcomposite plate reinforced by functionally graded single-walled carbon nanotube (FG-SWCNT) under hydro-thermal environments are investigated. The generalized rule of mixture is employed to predict mechanical, moisture and thermal properties of micro composite plate. The governing equations of motion are obtained using energy method and Hamilton’s principle, and solved by differential quadrature method (DQM). There is a good agreement between the obtained results and the other results. The influences of the material length scale, elastic foundation parameters and temperature and moisture changes for various boundary conditions on the natural frequency, Critical Buckling Load and deflection of the micro composite plate reinforced by FG-SWCNT are presented. The obtained results show that Critical Buckling Load and natural frequency for MSGT are more than that of for classic theory (CT) and modified coupled stress theory (MCST), and vice versa for the deflection. The material length scale parameters lead to increase the stiffness of system. Also the effect of moisture on microcomposite plate reinforced by SWCNT is similar to thermal effect; furthermore, with increasing of moisture change reduces the natural frequency and Critical Buckling Load and increases the deflection of micro composite plate. Considering the environmental conditions and temperature results are closer to reality.

  • electro elastic analysis of a sandwich thick plate considering fg core and composite piezoelectric layers on pasternak foundation using tsdt
    Steel and Composite Structures, 2016
    Co-Authors: M Mohammadimehr, Rasoul Rostami, Mohammad Arefi
    Abstract:

    Third order shear deformation theory is used to evaluate electro-elastic solution of a sandwich plate with considering functionally graded (FG) core and composite face sheets made of piezoelectric layers. The plate is resting on the Pasternak foundation and subjected to normal pressure. Short circuited condition is applied on the top and bottom of piezoelectric layers. The governing differential equations of the system can be derived using Hamilton`s principle and Maxwell`s equation. The Navier`s type solution for a sandwich rectangular thick plate with all edges simply supported is used. The numerical results are presented in terms of varying the parameters of the problem such as two elastic foundation parameters, thickness ratio (), and power law index on the dimensionless deflection, Critical Buckling Load, electric potential function, and the natural frequency of sandwich rectangular thick plate. The results show that the dimensionless natural frequency and Critical Buckling Load diminish with an increase in the power law index, and vice versa for dimensionless deflection and electrical potential function, because of the sandwich thick plate with considering FG core becomes more flexible; while these results are reverse for thickness ratio.

  • surface stress effect on the nonlocal biaxial Buckling and bending analysis of polymeric piezoelectric nanoplate reinforced by cnt using eshelby mori tanaka approach
    Journal of Solid Mechanics, 2015
    Co-Authors: M Mohammadimehr, Rousta B Navi, Ghorbanpour A Arani
    Abstract:

    In this article, the nonlocal biaxial Buckling Load and bending analysis of polymeric piezoelectric nanoplate reinforced by carbon nanotube (CNT) considering the surface stress effect is presented. This plate is subjected to electro-magneto-mechanical Loadings. Eshelby-Mori-Tanaka approach is used for defining the piezoelectric nanoplate material properties. Navier’s type solution is employed to obtain the Critical Buckling Load of polymeric piezoelectric nanoplate for classical plate theory (CPT) and first order shear deformation theory (FSDT). The influences of various parameters on the biaxial nonlocal Critical Buckling Load with respect to the local Critical Buckling Load ratio (

  • Buckling analysis of laminated composite rectangular plates reinforced by swcnts using analytical and finite element methods
    Journal of Mechanical Science and Technology, 2011
    Co-Authors: Ghorbanpour A Arani, M Mohammadimehr, Sh Maghamikia, A Arefmanesh
    Abstract:

    In this paper, the Buckling analysis of laminated composite plates reinforced by single-walled carbon nanotubes (SWCNTs) is carried out using an analytical approach as well as the finite element method. The developed model is based on the classical laminated plate theory (CLPT) and the third-order shear deformation theory for moderately thick laminated plates. The Critical Buckling Loads for the symmetrical layup are determined for different support edges. The Mori-Tanaka method is employed to calculate the effective elastic modulus of composites having aligned oriented straight nanotubes. The effect of the agglomeration of the randomly oriented straight nanotubes on the Critical Buckling Load is also analyzed. The results of analytical solution are compared and verified with the FEM calculations The Critical Buckling Loads obtained by the finite element and the analytical methods for different layup and boundary conditions are in good agreement with each other. In this article, the effects of the carbon nanotubes (CNTs) orientation angle, the edge conditions, and the aspect ratio on the Critical Buckling Load are also demonstrated using both the analytical and finite element methods.

Rousta B Navi - One of the best experts on this subject based on the ideXlab platform.

  • surface stress and agglomeration effects on nonlocal biaxial Buckling polymeric nanocomposite plate reinforced by cnt using various approaches
    Advanced Composite Materials, 2016
    Co-Authors: Ghorbanpour A Arani, Rousta B Navi, M Mohammadimehr
    Abstract:

    In this article, the surface stress effect on the biaxial Critical Buckling Load of nonlocal polymeric nanocomposite rectangular plate reinforced by carbon nanotubes (CNTs) is presented. Various approaches such as Eshelby–Mori–Tanaka, the extended mixture rule, Halpin–Tsai, and micromechanical are used to determine the effective material properties of polymeric nanocomposite plate. The governing equations of equilibrium are obtained by using Hamilton’s principle. The Navier’s method is considered to obtain the biaxial Critical Buckling Load of polymeric nanocomposite rectangular plate for simply supported boundary conditions. A detailed parametric study is conducted to explain the effects of aspect ratio, elastic foundation, surface stress and agglomeration on the biaxial Buckling of nanocomposite plate. The results show that surface stress effect plays an important role at nanoscale. Also, the biaxial Critical Buckling Load decreases with increasing the CNTs volume fraction in the inclusion (agglomeratio...

  • bending Buckling and free vibration analysis of msgt microcomposite reddy plate reinforced by fg swcnts with temperature dependent material properties under hydro thermo mechanical Loadings using dqm
    Composite Structures, 2016
    Co-Authors: M Mohammadimehr, M Salemi, Rousta B Navi
    Abstract:

    Abstract In this paper, using third-order shear deformation theory (TSDT) and modified strain gradient theory (MSGT), bending, Buckling and free vibration behaviors of microcomposite plate reinforced by functionally graded single-walled carbon nanotube (FG-SWCNT) under hydro-thermal environments are investigated. The generalized rule of mixture is employed to predict mechanical, moisture and thermal properties of micro composite plate. The governing equations of motion are obtained using energy method and Hamilton’s principle, and solved by differential quadrature method (DQM). There is a good agreement between the obtained results and the other results. The influences of the material length scale, elastic foundation parameters and temperature and moisture changes for various boundary conditions on the natural frequency, Critical Buckling Load and deflection of the micro composite plate reinforced by FG-SWCNT are presented. The obtained results show that Critical Buckling Load and natural frequency for MSGT are more than that of for classic theory (CT) and modified coupled stress theory (MCST), and vice versa for the deflection. The material length scale parameters lead to increase the stiffness of system. Also the effect of moisture on microcomposite plate reinforced by SWCNT is similar to thermal effect; furthermore, with increasing of moisture change reduces the natural frequency and Critical Buckling Load and increases the deflection of micro composite plate. Considering the environmental conditions and temperature results are closer to reality.

  • surface stress effect on the nonlocal biaxial Buckling and bending analysis of polymeric piezoelectric nanoplate reinforced by cnt using eshelby mori tanaka approach
    Journal of Solid Mechanics, 2015
    Co-Authors: M Mohammadimehr, Rousta B Navi, Ghorbanpour A Arani
    Abstract:

    In this article, the nonlocal biaxial Buckling Load and bending analysis of polymeric piezoelectric nanoplate reinforced by carbon nanotube (CNT) considering the surface stress effect is presented. This plate is subjected to electro-magneto-mechanical Loadings. Eshelby-Mori-Tanaka approach is used for defining the piezoelectric nanoplate material properties. Navier’s type solution is employed to obtain the Critical Buckling Load of polymeric piezoelectric nanoplate for classical plate theory (CPT) and first order shear deformation theory (FSDT). The influences of various parameters on the biaxial nonlocal Critical Buckling Load with respect to the local Critical Buckling Load ratio (

Jianzhong Zhao - One of the best experts on this subject based on the ideXlab platform.

  • a unified size dependent plate model based on nonlocal strain gradient theory including surface effects
    Applied Mathematical Modelling, 2019
    Co-Authors: Xingming Guo, Jianzhong Zhao
    Abstract:

    Abstract Based on the nonlocal strain gradient theory and surface elasticity theory, a unified size-dependent plate model is developed for Buckling analysis of rectangular nanoplates. The developed model is capable of capturing nonlocal effect, strain gradient effect as well as surface energy effects simultaneously. Moreover, by selecting appropriate shape function, the present model can be reduced to not only Kirchhoff and Mindlin plate models but also various higher-order shear deformation plate models. The non-classical governing equations and associated boundary conditions are established by using the principle of minimum potential energy. Analytical solutions for Critical Buckling Load of rectangular nanoplates under various boundary conditions are obtained. Verification of the proposed model is carried out by comparing the degenerated results with those reported in open literature. The effects of nonlocal parameter, material length scale parameter, geometric parameters, shear deformation and surface energy on the Buckling behavior of rectangular nanoplates under different boundary conditions are discussed in detail. The numerical results show that the Critical Buckling Load evaluated by nonlocal strain gradient theory is lower than that predicted by classical continuum theory when the nonlocal parameter is larger than the material length scale parameter, and is higher than that evaluated by classical continuum theory when the nonlocal parameter is smaller than the material length scale parameter. However, when taking surface effects into account, the Critical Buckling Load is mainly affected by surface effects at large length-to-thickness ratio, and depends on the combined effects of nonlocality, strain gradient and surface energy at small length-to-thickness ratio.

Davood Toghraie - One of the best experts on this subject based on the ideXlab platform.

  • comprehensive beam models for Buckling and bending behavior of simple nanobeam based on nonlocal strain gradient theory and surface effects
    Mechanics of Materials, 2019
    Co-Authors: Mohammad Hashemian, Shahin Foroutan, Davood Toghraie
    Abstract:

    Abstract In this paper, bending and Buckling behavior of nanobeam utilizing different beam theories including Timoshenko, Euler–Bernoulli, and higher-order beam theories are developed to investigate. The governing equations are derived based on nonlocal strain gradient theory incorporating surface effects. In order to solve the governing equation by a numerical solution, the Navier's method is utilized, and the simply supported boundary condition is imposed. Critical Buckling Load and maximum deflection are on the main concerns of this study. Obtained results represent the effect of surface, nonlocal, and length scale parameters. Moreover, various beam theories are evaluated, and their discrepancies are discussed. Results disclose that the Timoshenko and higher-order beam theories with negligible diversions are the Critical ones which predict the lowest Critical Buckling Load and highest maximum deflection compared to Euler–Bernoulli beam theory. As a primary result, residual surface stress and surface Young's modulus magnitude reveal a direct relation with material stiffness. Finally, as the small scale parameter increases the material stiffness decreases whereas increasing the length scale parameter stiffens the material structure.

F F Mahmoud - One of the best experts on this subject based on the ideXlab platform.

  • modeling and analysis of nanobeams based on nonlocal couple stress elasticity and surface energy theories
    International Journal of Mechanical Sciences, 2016
    Co-Authors: Mohamed A Attia, F F Mahmoud
    Abstract:

    Abstract This paper aims to develop a new non-classical Bernoulli–Euler model, taking into account the effects of a set of size dependent factors which ignored by the classical continuum mechanics. Among those factors are the microstructure local rotation, long-range interactions between a particle and the other particles of the continuum and the surface energy effects. The model used the modified couple-stress theory to study the effect of the local rotational degree of freedom of a specific particle. Furthermore, the surface elasticity model developed by Gurtin and Murdoch has been used to determine the surface energy effects on the behavior of the particle. The effects of the local rotation and surface energy are investigated in the framework of nonlocal elasticity theory, which is employed to study the nonlocal and long-range interactions between the particles. In addition, Poisson׳s effect incorporated in the newly developed beam model. The equations of equilibrium and complete boundary conditions of the new beam are derived using the principle of virtual work. The developed model is validated, by comparing the obtained results with benchmark results. To illustrate the new model, analytical solutions for the static bending and Critical Buckling Load are obtained. Numerical results reveal the significant effects of the nonlocal, microstructure, surface energy, length-to-height ratio and Poisson on the static bending and Critical Buckling Load of nanobeams.