Closed-form exact solutions for thick bi-directional functionally graded circular beams
07 Jan 2019-Multidiscipline Modeling in Materials and Structures (Emerald Publishing Limited)-Vol. 15, Iss: 1, pp 79-102
TL;DR: In this article, the authors extended the analytical model developed earlier to thick BDFG circular beams by using first-order shear deformation theory which allows for a non-zero shear strain distribution through the thickness of the beam.
Abstract: There exists a clear paucity of models for curved bi-directional functionally graded (BDFG) beams wherein the material properties vary along the axis and thickness of the beam simultaneously; such structures may help fulfil practical design requirements of the future and improve structural efficiency. In this context, the purpose of this paper is to extend the analytical model developed earlier to thick BDFG circular beams by using first-order shear deformation theory which allows for a non-zero shear strain distribution through the thickness of the beam.,Smooth functional variations of the material properties have been assumed along the axis and thickness of the beam simultaneously. The governing equations developed have been solved analytically for some representative determinate circular beams. In order to ascertain the effects of shear deformation in these structures, the total strain energy has been decomposed into its bending and shear components and the effects of the beam thickness and the arch angle on the shear energy component have been studied.,Closed-form exact solutions involving through-the-thickness integrals carried out numerically are presented for the bending of circular beams under the action of a variety of concentrated/distributed loads.,The results clearly indicate the importance of capturing shear deformation in thick BDFG beams and demonstrate the capability of tuning the response of these beams to fit a wide variety of structural requirements.
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TL;DR: In this article, a weighted residual approach (WRA) was employed to find the shear modulus variation to maximize the torsional stiffness for linear elastic boundary value problem.
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TL;DR: In this article , a warping included mixed finite element formulation for the static and stress analyses of functionally graded (FG) exact curved beams is presented, where the constitutive equations are derived from the 3D elasticity theory of an elastic continuum.
Abstract: This study presents a warping included mixed finite element formulation for the static and stress analyses of functionally graded (FG) exact curved beams. Another distinctive feature of this study is to present the range of geometric and material parameters where the first-order shear deformation theory lacks necessary precision. The constitutive equations are derived from the 3D elasticity theory of an elastic continuum. The couple effects are considered in addition to the variations of FG material constituents through the transverse/axial directions. The mixed finite element formulation is enhanced by the cross-sectional warping deformations over a displacement-type finite element formulation. The two-noded curved mixed finite elements with 12 degrees of freedom at per node are derived over exact curvature and length. Satisfactory results are obtained for the static responses and stresses of axially FG-sandwich and transversely FG exact curved beams with power-law dependence compared to the 3D behavior of brick finite elements. Finally, the influences of ellipticity, width to thickness ratio, FG material constituents, and material gradient index on the static response of FG exact curved beams are investigated.
TL;DR: In this paper , a tangent shape function-based higher-order transverse shear deformation theory (NTHSDT) is proposed to compute the buckling behavior of the elastically supported functionally graded material (FGM) sandwich plates under porous medium.
Abstract: In this paper, new tangent shape function-based higher-order transverse shear deformation theory (NTHSDT) is proposed to compute the buckling behavior of the elastically supported functionally graded material (FGM) sandwich plates under porous medium. The proposed theory is found to be variationally consistent and fulfills the zero traction boundary conditions on the bottom and top layer without a shear correction factor. The material properties are presumed to be graded in the thickness direction as characterized by a modified power law distribution in terms of volume fraction of constituents. The governing equations are derived using Hamilton’s Principle. A strong form of solution discretizes the governing equations by employing a thin plate spline radial basis function-based collocation (TSRBFC) method. The proposed theory is efficient, reliable, and is in close agreement with the results in the literature. Comparison studies show that the NTHSDT is more accurate than other plate theories and is simple in analyzing buckling behavior. A parametric study is done to examine the effects of grading index, porosity index, sandwich schemes, aspect ratio, side-to-length thickness ratio and foundation stiffness.
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01 Jan 1892TL;DR: Webb's work on elasticity as mentioned in this paper is the outcome of a suggestion made to me some years ago by Mr R. R. Webb that I should assist him in the preparation of a work on Elasticity.
Abstract: The present treatise is the outcome of a suggestion made to me some years ago by Mr R. R. Webb that I should assist him in the preparation of a work on Elasticity. He has unfortunately found himself unable to proceed with it, and I have therefore been obliged to take upon myself the whole of the work and the whole of the responsibility. I wish to acknowledge at the outset the debt that I owe to him as a teacher of the subject, as well as my obligation for many valuable suggestions chiefly with reference to the scope and plan of the work, and to express my regret that other engagements have prevented him from sharing more actively in its production.
The division of the subject adopted is that originally made by Clebsch in his classical treatise, where a clear distinction is ill-awn between exact solutions for bodies all whose dimensions are finite and approximate solutions for bodies some of whose dimensions can be regarded as infinitesimal. The present volume contains the general mathematical theory of the elastic properties of the first class of bodies, and I propose to treat the second class in another volume. At Mr Webb's suggestion, the exposition of the theory is preceded by an historical sketch of its origin and development. Anything like an exhaustive history has been rendered unnecessary by the work of the late Dr Todhunter as edited by Prof Karl Pearson, but it is hoped that the brief account given will at once facilitate the comprehension of the theory and add to its interest.
Readers of the historical work referred to will appreciate the difficulty of giving within a reasonable compass a complete account of all the valuable researches that have been made; and the aim of this book is rather to present a connected account of the theory in its present state, and an indication of the way in which that state has been attained, avoiding on the one hand merely analytical developments, and on the other purely technical details.
7,269 citations
1,602 citations
TL;DR: In this article, an elasticity solution for a functionally graded beam subjected to transverse loads is obtained, where Young's modulus of the beam is assumed to vary exponentially through the thickness, and the Poisson ratio is held constant.
603 citations
TL;DR: In this paper, a three-dimensional exact solution for free and forced vibrations of simply supported functionally graded rectangular plates is presented, where suitable displacement functions that identically satisfy boundary conditions are used to reduce equations governing steady state vibrations of a plate to a set of coupled ordinary differential equations, which are then solved by employing the power series method.
544 citations
TL;DR: In this article, a beam element based on first-order shear deformation theory is developed to study the thermoelastic behavior of functionally graded beam structures, and the stiffness matrix has super-convergent property and the element is free of shear locking.
521 citations