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Article Citation - WoS: 20Citation - Scopus: 20The Stress Response of Partially Plastic Rotating Fgm Hollow Shafts: Analytical Treatment for Axially Constrained Ends(Taylor & Francis inc, 2006) Eraslan, Ahmet N.; Akis, Tolgaanalytical solutions to estimating the elastoplastic response of rotating functionally graded (FGM) hollow shafts with fixed ends are presented. The modulus of elasticity, as well as the uniaxial yield limit of the shaft material, are assumed to vary nonlinearly in the radial direction. The plastic model is based on Tresca's yield criterion, its associated flow rule, and ideal plastic material behaviour. Elastic, partially plastic, fully plastic, and residual stress states are investigated. It is shown that the elastoplastic stress response of a rotating FGM hollow shaft is affected significantly by the nonhomogeneity of the material. Unlike the case of a homogeneous hollow shaft, plastic deformation may commence at the inner surface, at the outer surface, or simultaneously at both surfaces. Accordingly, each case requires different mathematical treatment to arrive at its partially plastic solution. It is also shown that, by taking a numerical limit, the complete FGM solution presented herein converge to the solution of a homogeneous rotating shaft.Article Citation - WoS: 33Citation - Scopus: 35Exact Solution of Rotating Fgm Shaft Problem in the Elastoplastic State of Stress(Springer, 2007) Akis, Tolga; Eraslan, Ahmet N.Plane strain analytical solutions to estimate purely elastic, partially plastic and fully plastic deformation behavior of rotating functionally graded (FGM) hollow shafts are presented. The modulus of elasticity of the shaft material is assumed to vary nonlinearly in the radial direction. Tresca's yield criterion and its associated flow rule are used to formulate three different plastic regions for an ideal plastic material. By considerina different material compositions as well as a wide range of bore radii, it is demonstrated in this article that both the elastic and the elastoplastic responses of a rotating FGM hollow shaft are affected significantly by the material nonhomogeneity.Article Citation - Scopus: 35Elastoplastic Response of a Long Functionally Graded Tube Subjected To Internal Pressure(2005) Eraslan,A.N.; Akis,T.Plane strain analytical solutions to functionally graded elastic and elastic-plastic pressurized tube problems are obtained in the framework of small deformation theory. The modulus of elasticity of the tube material is assumed to vary radially according to a 2 parametric model in a general parabolic form. The analytical plastic model is based on Tresca's yield criterion, its associated flow rule and ideally plastic material behavior. Exact solutions of field equations for elastic and plastic deformations are obtained. It is shown that the elastoplastic response of the functionally graded pressurized tube is affected notably by the radial variation of modulus of elasticity. It is also shown mathematically that the nonhomogeneous solution presented here reduces to that of a homogeneous one by the appropriate choice of the material parameters. © TÜBİTAK.Article Citation - WoS: 47Citation - Scopus: 46Elastoplastic Analysis of Functionally Graded Spherical Pressure Vessels(Elsevier Science Bv, 2009) Akis, TolgaPurely elastic, partially plastic and fully plastic stress states of internally pressurized functionally graded spherical pressure vessels are investigated analytically in the framework of small deformation theory. The modulus of elasticity and the uniaxial yield limit of the spherical pressure vessel material are assumed to vary nonlinearly in the radial direction. The plastic model is based on Tresca's yield criterion and ideal plastic material behavior. It is shown that, unlike in the case of a homogeneous spherical pressure vessel, different modes of plasticization may take place due to the radial variation of the functionally grading parameters. (C) 2009 Elsevier B.V. All rights reserved.Article Citation - Scopus: 13Deformation Analysis of Elastic-Plastic Two Layer Tubes Subject To Pressure: an Analytical Approach(2004) Eraslan,A.N.; Akiş,T.Analytical solutions are obtained for axisymmetric elastic-plastic deformations in tightly fitted concentric tubes with fixed ends subjected to either internal or external pressure. Tresca's yield criterion and its associated flow rule are used to estimate the elastic-plastic response of the assembly. The closed form solutions for all elastic-plastic deformation stages are obtained by assuming linear hardening material behavior. Some numerical examples are handled using the mechanical properties of real engineering materials.Article Citation - WoS: 50Citation - Scopus: 55Plane Strain Analytical Solutions for a Functionally Graded Elastic-Plastic Pressurized Tube(Elsevier Sci Ltd, 2006) Eraslan, Ahmet N.; Akis, TolgaPlane strain analytical solutions to functionally graded elastic and elastic-plastic pressurized tube problems are obtained in the framework of small deformation theory. The modulus of elasticity and the uniaxial yield limit of the tube material are assumed to vary radially according to two parametric parabolic forms. The analytical plastic model is based on Tresca's yield criterion, its associated flow rule and ideally plastic material behaviour. Elastic, partially plastic and fully plastic stress states are investigated. It is shown that the elastoplastic response of the functionally graded pressurized tube is affected significantly by the material nonhomogeneity. Different modes of plasticization may take place unlike the homogeneous case. It is also shown mathematically that the nonhomogeneous elastoplastic solution presented here reduces to that of a homogeneous one by appropriate choice of the material parameters. (c) 2006 Elsevier Ltd. All rights reserved.Article Citation - Scopus: 1Yielding of Functionally Graded Long Tubes Under Thermal Loading;(2006) Akiş,T.The elastic behavior of a functionally graded non-uniform heat generating long tube is investigated analytically. The thermal conductivity and the modulus of elasticity of the tube material are assumed to vary radially in nonlinear forms. Making use of Tresca's yield criterion, the effect of grading parameters on the yielding behavior of the tube is investigated. It is observed that plastic flow may commence at the inner surface, at the outer surface or inside the tube depending on the functionally grading parameters.
