Iranian Society of Mechanical EngineeringIranian Journal of Mechanical Engineering Transactions of the ISME1605-972712220110901A General Form Solution for Elastic Buckling of Thin Cylinders Made of FGM under Axial Loading62620555ENR.ShahsiahDepartment of Mechanical Engineering, Islamic Azad University, Central Tehran Branch, Tehran, IranJournal Article20110401In this article, the axisymmetric mechanical buckling of thin cylindrical shell made of functionally graded material (FGM) is considered. The governing equations for a thin cylinder based on the first-order shell theory and Timoshenko's assumptions are obtained. The equations are derived using the Sanders simplified kinematic relations and the principle of work and energy. The constituent material of the functionally graded shell is assumed to be a mixture of ceramic and metal. It is assumed that the mechanical properties vary continuously through the shell thickness. The thin cylindrical shell is under uniform axial compressive load. The expression for the critical mechanical buckling load is obtained analytically and is given by closed form solution. The results are validated with the Timoshenko's formula in the literature.http://jmee.isme.ir/article_20555_25e8a8fc68fc1bace5f71a47226ef1ca.pdfIranian Society of Mechanical EngineeringIranian Journal of Mechanical Engineering Transactions of the ISME1605-972712220110901Thermo-elastic analysis of a functionally graded thick sphere by differential quadrature method274320556ENR.Akbari AlashtiBabol University of Technology, Babol, IranM.KhorsandBabol University of Technology, Babol, IranM. H.TarahhomiBabol University of Technology, Babol, IranJournal Article20110401<span style="font-family: Tahoma, Verdana, Arial, Helvetica, sans-serif;">Thermo-elastic analysis of a functionally graded hollow sphere is carried out and numerical solutions of displacement, stress and thermal fields are obtained using the Polynomial differential quadrature (PDQ) method. Material properties are assumed to be graded in the radial direction according to a power law function, however the Poisson’s ratio is assumed to be constant. The governing partial differential equations are obtained in terms of displacement and temperature fields and expressed in the form of series equations. A comparison of numerical results with the analytical and finite element results is presented that shows an excellent agreement. The effect of the material grading parameter, temperature variation and thickness of the sphere on the distribution of stress, radial displacement and temperature fields is investigated.</span><br /> <br /> <br /> <br /> <br /> <br /> <em><span style="font-size: 12.0pt; font-family: 'Times New Roman',serif;">Thermo-elastic analysis of a functionally graded hollow sphere is carried out and numerical solutions of displacement, stress and thermal fields are obtained using the Polynomial differential quadrature </span></em><em><span style="font-family: 'Times New Roman',serif;">(PDQ)</span></em><em><span style="font-size: 12.0pt; font-family: 'Times New Roman',serif;"> method. Material properties are assumed to be graded in the radial direction according to a power law function, however the Poisson’s ratio is assumed to be constant. The governing partial differential equations are obtained in terms of displacement and temperature fields and expressed in the form of series equations. A comparison of numerical results with the analytical and finite element results is presented that shows an excellent agreement. The effect of the material grading parameter, temperature variation and thickness of the sphere on the distribution of stress, radial displacement and temperature fields is investigated.</span></em>http://jmee.isme.ir/article_20556_e540ada6db47c1c44d427937fc6d2faa.pdfIranian Society of Mechanical EngineeringIranian Journal of Mechanical Engineering Transactions of the ISME1605-972712220110901Analytical Modeling of Axial Collapse of Circular Hybrid Tubes445320557ENM.MirzaeiAssistant Professor, Department of Mechanical Engineering, Damavand Branch, Islamic Azad University, Damavand, IranH.AkbarshahiDepartment of Mechanical Engineering, Amirkabir University of Technology, Tehran, IranM.ShakeriDepartment of Mechanical Engineering, Amirkabir University of Technology, Tehran, IranM.SadighiDepartment of Mechanical Engineering, Amirkabir University of Technology, Tehran, IranJournal Article20110401In this paper, considering symmetric collapse mode for hybrid tubes, and using Tsai-Hill fracture criterion to take into account the off-axis strength of an orthotropic lamina, an analytical model is extended and an expression is derived for mean crushing load and fold lengths of circular hybrid tubes. In this model, the influences of the geometrical dimensions including diameter, thickness of metal and composite wall, fiber ply orientation and material properties are studied on the mean crushing load and fold lengths. The validation with the previously published results provides reasonably good agreement.http://jmee.isme.ir/article_20557_a9076a687c941dc720ea94bf64b23643.pdfIranian Society of Mechanical EngineeringIranian Journal of Mechanical Engineering Transactions of the ISME1605-972712220110901A Linear Approach to the Control of Vortex Induced Vibrations of Circular Cylinders with a 2-D Van der Pol Model for Structural Oscillator547220558ENA.FarshidianfarMechanical Engineering Department, Engineering Faculty, Ferdowsi University of Mashhad, IranN.DolatabadiMechanical Engineering Department, Engineering Faculty, Ferdowsi University of Mashhad, IranJournal Article20110401In the present paper, a new 2-D Van der Polstructural oscillator model is introduced for the vortex induced vibrations of circular cylinders.The main purpose of this task is to control the recently introduced model by means of modern control definitions in state space. In order to control the system, the whole model is linearized about its equilibrium point by deriving state-space matrices. Then, the linear transfer function is obtained and controlled by pole-placement technique which is based on the state variables feedback. Afterwards, this linear controller is applied to the nonlinear system about its equilibrium point by assuming that there is no uncertainty in both physical and mathematical models. Eventually,the results for linear and nonlinear systems are compared.http://jmee.isme.ir/article_20558_a23e8eb83ae0f1528ee73d5a370990d1.pdfIranian Society of Mechanical EngineeringIranian Journal of Mechanical Engineering Transactions of the ISME1605-972712220110901Thermoelastic Analysis in Thick FGM Cylinders with Extended Profile739120559ENR.PoultangariDepartment of Mechanical Engineering, Islamic Azad University, Dezful Branch, Iran,A.BahtuiSystem and Design Department, Brunel University, Middlesex, UB8 7RH, UKM. R.EslamiME Dept., Amirkabir University of Technology, Tehran, IranJournal Article20110701An exact solution is obtained for an axisymmetric steady-state thermo-mechanical stresses in a thick functionally graded cylinder. The material properties are graded along the radial direction according to an exponential function of radial direction with three constants. The advantage of the proposed model, compared to the models with two constants such as the linear, power law, and exponential models with two constants, is that it satisfies the material boundary conditions at the inside and outside radiuses, leaving one more constant to be selected to produce different types of material variation profiles along the cylinder radius. Utilizing the assumed exponential model, the analytical solution of the problem, using the generalized Bessel function and the Lagrange method, is obtained employing the energyand Navier equations.http://jmee.isme.ir/article_20559_64a57b90d1fd789dedbbadc9c7f6c295.pdf