Buckling Analysis of Orthotropic Nanoscale Plates Resting on Elastic Foundations

2018 ◽  
Vol 55 ◽  
pp. 42-56 ◽  
Author(s):  
Belkacem Kadari ◽  
Aicha Bessaim ◽  
Abdelouahed Tounsi ◽  
Houari Heireche ◽  
Abdelmoumen Anis Bousahla ◽  
...  
Keyword(s):  
Shear Deformation ◽  
Deformation Theory ◽  
Scale Effects ◽  
Plate Theory ◽  
Constitutive Relations ◽  
Shear Deformation Theory ◽  
Nonlocal Elasticity Theory ◽  
Higher Order ◽  
Small Scale ◽  
Classical Plate Theory

This work presents the buckling investigation of embedded orthotropic nanoplates by using a new hyperbolic plate theory and nonlocal small-scale effects. The main advantage of this theory is that, in addition to including the shear deformation effect, the displacement field is modeled with only three unknowns and three governing equation as the case of the classical plate theory (CPT) and which is even less than the first order shear deformation theory (FSDT) and higher-order shear deformation theory (HSDT). A shear correction factor is, therefore, not required. Nonlocal differential constitutive relations of Eringen is employed to investigate effects of small scale on buckling of the rectangular nanoplate. The elastic foundation is modeled as two-parameter Pasternak foundation. The equations of motion of the nonlocal theories are derived and solved via Navier's procedure for all edges simply supported boundary conditions. The proposed theory is compared with other plate theories. Analytical solutions for buckling loads are obtained for single-layered graphene sheets with isotropic and orthotropic properties. The results presented in this study may provide useful guidance for design of orthotropic graphene based nanodevices that make use of the buckling properties of orthotropic nanoplates. Verification studies show that the proposed theory is not only accurate and simple in solving the buckling nanoplates, but also comparable with the other higher-order shear deformation theories which contain more number of unknowns. Keywords: Buckling; orthotropic nanoplates; a simple 3-unknown theory; nonlocal elasticity theory; Pasternak’s foundations. * Corresponding author; [email protected]

Enhanced First-Order Shear Deformation Theory for Laminated and Sandwich Plates

2005 ◽  
Vol 72 (6) ◽  
pp. 809-817 ◽  
Author(s):  
Jun-Sik Kim ◽  
Maenghyo Cho
Keyword(s):  
Shear Deformation ◽  
Deformation Theory ◽  
Plate Theory ◽  
Three Dimensional ◽  
Shear Deformation Theory ◽  
Higher Order ◽  
Laminated Plates ◽  
Sandwich Plates ◽  
First Order ◽  
Transverse Shear Strains

A new first-order shear deformation theory (FSDT) has been developed and verified for laminated plates and sandwich plates. Based on the definition of Reissener–Mindlin’s plate theory, the average transverse shear strains, which are constant through the thickness, are improved to vary through the thickness. It is assumed that the displacement and in-plane strain fields of FSDT can approximate, in an average sense, those of three-dimensional theory. Relationship between FSDT and three-dimensional theory has been systematically established in the averaged least-square sense. This relationship provides the closed-form recovering relations for three-dimensional variables expressed in terms of FSDT variables as well as the improved transverse shear strains. This paper makes two main contributions. First an enhanced first-order shear deformation theory (EFSDT) has been developed using an available higher-order plate theory. Second, it is shown that the displacement fields of any higher-order plate theories can be recovered by EFSDT variables. The present approach is applied to an efficient higher-order plate theory. Comparisons of deflection and stresses of the laminated plates and sandwich plates using present theory are made with the original FSDT and three-dimensional exact solutions.

A NEW TRIANGULAR ELEMENT BASED ON HIGHER ORDER SHEAR DEFORMATION THEORY FOR FLEXURAL VIBRATION OF COMPOSITE PLATES

2002 ◽  
Vol 02 (02) ◽  
pp. 163-184 ◽  
Author(s):  
A. CHAKRABARTI ◽  
A. H. SHEIKH
Keyword(s):  
Shear Deformation ◽  
Vibration Analysis ◽  
Deformation Theory ◽  
Plate Theory ◽  
Plate Thickness ◽  
Shear Deformation Theory ◽  
Free Vibration Analysis ◽  
Composite Plates ◽  
Higher Order ◽  
Triangular Element

A triangular element based on Reddy's higher order shear deformation theory is developed for free vibration analysis of composite plates. In the Reddy's plate theory, the transverse shear stress varies in a parabolic manner across the plate thickness and vanishes at the top and bottom surfaces of the plate. Moreover, it does not involve any additional unknowns. Thus the plate theory is quite simple and elegant. Unfortunately, such an attractive plate theory cannot be exploited as expected in finite element analysis, primarily due to the difficulties in satisfying the inter-element continuity requirement. This has inspired us to develop the present element, which has three corner nodes and three mid-side nodes with the same number of degrees of freedom. To demonstrate the performance of the element, numerical examples of isotropic and composite plates under different situations are solved. The results are compared with the analytical solutions and other published results, which show the accuracy and range of applicability of the proposed element in the problem of vibration analysis.

Nonlinear Vibration Analysis of Nano-Disks Based on Nonlocal Elasticity Theory Using Homotopy Perturbation Method

2019 ◽  
Vol 11 (02) ◽  
pp. 1950011 ◽  
Author(s):  
Mohammad Shishesaz ◽  
Mojtaba Shariati ◽  
Amin Yaghootian ◽  
Ali Alizadeh
Keyword(s):  
Perturbation Method ◽  
Elasticity Theory ◽  
Nonlocal Elasticity ◽  
Scale Effects ◽  
Plate Theory ◽  
Free Field ◽  
Nonlocal Elasticity Theory ◽  
Polar Coordinates ◽  
Small Scale ◽  
Classical Plate Theory

This paper introduces a novel approach for small-scale effects on nonlinear free-field vibration of a nano-disk using nonlocal elasticity theory. The formulation of a nano-disk is based on the nonlinear model of von Kármán strain in polar coordinates and classical plate theory. To analyze the nonlinear geometric and small-scale effects, the differential equation based on nonlocal elasticity theory was extracted from Hamilton principle, while the inertial and shear-stress effects were neglected. The equation of motion was discretized using the Galerkin method on selecting an appropriate function based on the boundary condition used for the nano-disk. Due to presence of nonlinear terms, the homotopy method was used in conjunction with the perturbation method (HPM) to ease up the solution and completely solve the problem. For further comparison, the nonlinear equations were solved by the fourth-order Runge–Kutta method, the solution of which was compared with that of HPM. Excellent agreements in results were observed between the two methods, indicating that the latter method can simplify the solution, and hence, can be applied to nonlinear nano-disk problems to seek their solution with a high accuracy.

scholarly journals Nonlocal Elasticity Theory for Transient Analysis of Higher-Order Shear Deformable Nanoscale Plates

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Woo-Young Jung ◽  
Sung-Cheon Han
Keyword(s):  
Dynamic Response ◽  
Shear Deformation ◽  
Nonlocal Elasticity ◽  
Deformation Theory ◽  
Transient Analysis ◽  
Shear Deformation Theory ◽  
Nonlocal Theory ◽  
Higher Order ◽  
Small Scale ◽  
Nano Scale

The small scale effect on the transient analysis of nanoscale plates is studied. The elastic theory of the nano-scale plate is reformulated using Eringen’s nonlocal differential constitutive relations and higher-order shear deformation theory (HSDT). The equations of motion of the nonlocal theories are derived for the nano-scale plates. The Eringen’s nonlocal elasticity of Eringen has ability to capture the small scale effects and the higher-order shear deformation theory has ability to capture the quadratic variation of shear strain and consequently shear stress through the plate thickness. The solutions of transient dynamic analysis of nano-scale plate are presented using these theories to illustrate the effect of nonlocal theory on dynamic response of the nano-scale plates. On the basis of those numerical results, the relations between nonlocal and local theory are investigated and discussed, as are the nonlocal parameter, aspect ratio, side-to-thickness ratio, nano-scale plate size, and time step effects on the dynamic response. In order to validate the present solutions, the reference solutions are employed and examined. The results of nano-scale plates using the nonlocal theory can be used as a benchmark test for the transient analysis.

scholarly journals Some Inconsistencies in the Nonlinear Buckling Plate Theories—FSDT, S-FSDT, HSDT

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2154
Author(s):  
Zbigniew Kolakowski ◽  
Jacek Jankowski
Keyword(s):  
Shear Deformation ◽  
Composite Structures ◽  
Deformation Theory ◽  
Plate Theory ◽  
Shear Deformation Theory ◽  
Nonlinear Problems ◽  
Classical Plate Theory ◽  
Nonlinear Buckling ◽  
First Order ◽  
Membrane Components

Bending and membrane components of transverse forces in a fixed square isotropic plate under simultaneous compression and transverse loading were established within the first-order shear deformation theory (FSDT), the simple first-order shear deformation theory (S-FSDT), and the classical plate theory (CPT). Special attention was drawn to the fact that bending components were accompanied by transverse deformations, whereas membrane components were not, i.e., the plate was transversely perfectly rigid. In the FSDT and the S-FSDT, double assumptions concerning transverse deformations in the plate hold. A new formulation of the differential equation of equilibrium with respect to the transverse direction of the plate, using a variational approach, was proposed. For nonlinear problems in the mechanics of thin-walled plates, a range where membrane components should be considered in total transverse forces was determined. It is of particular significance as far as modern composite structures are concerned.

scholarly journals Effect of Membrane Components of Transverse Forces on Magnitudes of Total Transverse Forces in the Nonlinear Stability of Plate Structures

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5262
Author(s):  
Zbigniew Kołakowski ◽  
Jacek Jankowski
Keyword(s):  
Shear Deformation ◽  
Deformation Theory ◽  
Plate Theory ◽  
Shear Deformation Theory ◽  
The Finite Element Method ◽  
Classical Plate Theory ◽  
Plate Structures ◽  
First Order ◽  
Membrane Components ◽  
Membrane Deformations

For an isotropic square plate subject to unidirectional compression in the postbuckling state, components of transverse forces in bending, membrane transverse components and total components of transverse forces were determined within the first-order shear deformation theory (FSDT), the simple first-order shear deformation theory (S-FSDT), the classical plate theory (CPT) and the finite element method (FEM). Special attention was drawn to membrane components of transverse forces, which are expressed with the same formulas for the first three theories and do not depend on membrane deformations. These components are nonlinearly dependent on the plate deflection. The magnitudes of components of transverse forces for the four theories under consideration were compared.

A Finite Element Modeling of Higher Order Shear Deformation Theory on a Plate Vibration Problem

1991 ◽  
Author(s):  
Chiang-Nan Chang ◽  
Thien-Rhei Chen
Keyword(s):  
Finite Element ◽  
Finite Element Modeling ◽  
Shear Deformation ◽  
Deformation Theory ◽  
Plate Theory ◽  
Shear Deformation Theory ◽  
Higher Order ◽  
Plate Vibration ◽  
Element Modeling ◽  
Plate Vibration Problem

Abstract Higher order Shear Defamation Plate Theories (HSDPT) are improved theories over Mindlin plate theory because their assumptions are closer to reality. However, they are seldom used in solving ordinary engineering works. This is due to the fact that mathematical formulations and computations are so lengthy that time and efforts required are close to solving a exact 3-D model. For problems involving sharp stress variation, higher order theories are anticipated to give better results. The combination of HSDPT and Finite Element Modelings are especially attractive because a finite element modeling is much simpler. The current research develops a finite element model on the higher order shear deformation theory. A plate vibration problem was solved. The plates contain square interior cutout. Stress distributions are much complicated than whole plates. Results of HSDPT are compared with FSDPT (First order Shear Deformation Plate Theories) and CPT (Classical Plate Theory). Better accuracies are obtained by using the HSDPT.

Large Deflection Behavior of Relatively Thick Functionally Graded Plates under Pressure Loads Using Higher Order Shear Deformation Theory

2011 ◽  
Vol 471-472 ◽  
pp. 709-714 ◽  
Author(s):  
Mohammad Homayoun Sadr-Lahidjani ◽  
Mohammad Hajikazemi ◽  
Mona Ramezani-Oliaee
Keyword(s):  
Shear Deformation ◽  
Deformation Theory ◽  
Large Deflection ◽  
Plate Theory ◽  
Shear Deformation Theory ◽  
Higher Order ◽  
Functionally Graded ◽  
Rectangular Plates ◽  
Functionally Graded Plates ◽  
Power Law Distribution

Large deflection analysis of thin and relatively thick rectangular functionally graded plates is studied in this paper. It is assumed that the mechanical properties of the plate, graded through the thickness, are described by a simple power law distribution in terms of the volume fractions of constituents. The plate is assumed to be under lateral pressure load. The fundamental equations for rectangular plates of FGM are obtained using the classical laminated plate theory (CLPT), first order shear deformation theory (FSDT) and higher order shear deformation theory (HSDT) for large deflection and the solution is obtained by minimization of the total potential energy.

Two-Dimensional Electro-Elastic Analysis of FG-CNTRC Cylindrical Laminated Pressure Vessels With Piezoelectric Layers Based on Third-Order Shear Deformation Theory

2019 ◽  
Vol 142 (2) ◽  
Author(s):  
Masoud Mohammadi ◽  
Mohammad Arefi ◽  
Sara Amir Ahmadi
Keyword(s):  
Shear Deformation ◽  
Deformation Theory ◽  
Constitutive Relations ◽  
Shear Deformation Theory ◽  
Pressure Vessels ◽  
Higher Order ◽  
Functionally Graded ◽  
Numerical Results ◽  
Third Order ◽  
Piezoelectric Layers

Abstract The purpose of this paper is to show the electro-elastic static behavior of cylindrical sandwich pressure vessels integrated with piezoelectric layers. The core is made of functionally graded carbon nanotube-reinforced composite (FG-CNTRC). The cylinder is embedded between two piezoelectric layers made of PZT-4. The effective material properties of reinforced core with carbon nanotubes (CNTs) are calculated based on rule of mixture. The constitutive relations are developed in cylindrical coordinate system based on a higher-order shear deformation theory for both core and piezoelectric layers. The employed higher-order theory is based on third-order variation of deformations along the thickness direction to improve the accuracy of numerical results. The method of eigenvalue–eigenvector is used for solution of system of governing equations along the longitudinal direction. The numerical results are provided along the longitudinal and radial directions in terms of significant parameters such as various patterns of CNTs, various volume fractions of CNTs, various elastic foundation coefficients, and various applied electrical potentials.

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