Islamic Azad University - Arak BranchJournal of Solid Mechanics2008-35052420101230Electro-magneto-thermo-mechanical Behaviors of a Radially Polarized FGPM Thick Hollow Sphere305315514387ENAGhorbanpour AraniDepartment of Mechanical Engineering, Faculty of Engineering, University of KashanJJafari FesharakiDepartment of Mechanical Engineering, Faculty of Engineering, University of KashanMMohammadimehrDepartment of Mechanical Engineering, Faculty of Engineering, University of KashanSGolabiDepartment of Mechanical Engineering, Faculty of Engineering, University of KashanJournal Article20100925In this study an analytical method is developed to obtain the response of electro-magneto-thermo-elastic stress and perturbation of a magnetic field vector for a thick-walled spherical functionally graded piezoelectric material (FGPM). The hollow sphere, which is placed in a uniform magnetic field, is subjected to a temperature gradient, inner and outer pressures and a constant electric potential difference between its inner and outer surfaces. The thermal, piezoelectric and mechanical properties except the Poisson’s ratio are assumed to vary with the power law functions through the thickness of the hollow sphere. By solving the heat transfer equation, in the first step, a symmetric distribution of temperature is obtained. Using the infinitesimal electro-magneto-thermo-elasticity theory, then, the Navier’s equation is solved and exact solutions for stresses, electric displacement, electric potential and perturbation of magnetic field vector in the FGPM hollow sphere are obtained. Moreover, the effects of magnetic field vector, electric potential and material in-homogeneity on the stresses and displacements distributions are investigated. The presented results indicate that the material in-homogeneity has a significant influence on the electro-magneto-thermo-mechanical behaviors of the FGPM hollow sphere and should therefore be considered in its optimum design.http://jsm.iau-arak.ac.ir/article_514387_329bd03d3729030ec7e3b5d21ca2d8ae.pdfIslamic Azad University - Arak BranchJournal of Solid Mechanics2008-35052420101230Stress Analysis of Two-directional FGM Moderately Thick Constrained Circular Plates with Non-uniform Load and Substrate Stiffness Distributions316331514388ENM.MAlipourFaculty of Mechanical Engineering, K.N. Toosi University of TechnologyMShariyatFaculty of Mechanical Engineering, K.N. Toosi University of TechnologyJournal Article20101004In the present paper, bending and stress analyses of two-directional functionally graded (FG) circular plates resting on non-uniform two-parameter foundations (Winkler-Pasternak foundations) are investigated using a first-order shear-deformation theory. To enhance the accuracy of the results, the transverse stress components are derived based on the three dimensional theory of elasticity. The solution is obtained by employing the differential transform method (DTM). The material properties are assumed to vary in both transverse and radial directions according to power and exponential laws, respectively. Intensity of the transverse load is considered to vary according to a second-order polynomial. The performed convergence analysis and the comparative studies demonstrate the high accuracy and high convergence rate of the approach. A sensitivity analysis consisting of evaluating effects of different parameters (e.g., exponents of the material properties, thickness to radius ratio, trend of variations of the foundation stiffness, and edge conditions) is carried out. Results reveal that in contrast to the available constitutive-law-based solutions, present solution guarantees continuity of the transverse stresses at the interfaces between layers and may also be used for stress analysis of the sandwich panels. The results are reported for the first time and are discussed in detail.http://jsm.iau-arak.ac.ir/article_514388_4b34b9f1216453272e39c4cac5a5effb.pdfIslamic Azad University - Arak BranchJournal of Solid Mechanics2008-35052420101230Elastic Buckling Analysis of Ring and Stringer-stiffened Cylindrical Shells under General Pressure and Axial Compression via the Ritz Method332347514389ENAGhorbanpour AraniDepartment of Mechanical Engineering, Faculty of Engineering, University of KashanALoghmanDepartment of Mechanical Engineering, Faculty of Engineering, University of Kashan0000-0002-8292-8958A.AMosallaie BarzokiDepartment of Mechanical Engineering, Faculty of Engineering, University of KashanRKolahchiDepartment of Mechanical Engineering, Faculty of Engineering, University of KashanJournal Article20100925Elastic stability of ring and stringer-stiffened cylindrical shells under axial, internal and external pressures is studied using Ritz method. The stiffeners are rings, stringers and their different arrangements at the inner and outer surfaces of the shell. Critical buckling loads are obtained using Ritz method. It has been found that the cylindrical shells with outside rings are more stable than those with inside rings under axial compressive loading. The critical buckling load for inside rings is reducing by increasing the eccentricity of the rings, while for outside ring stiffeners the magnitude of eccentricity does not affect the critical buckling load. It has also been found that the shells with inside stringers are more stable than those with outside one. Moreover, the stability of cylindrical shells under internal and external pressures is almost the same for inside and outside arrangements of stringers. The results are verified by comparing with the results of Singer at the same loading and boundary conditions.http://jsm.iau-arak.ac.ir/article_514389_43b417c7db9bf970e94eeaf63427c66d.pdfIslamic Azad University - Arak BranchJournal of Solid Mechanics2008-35052420101230Boundary Value Problems in Generalized Thermodiffusive Elastic Medium348362514390ENKSharmaDepartment of Mechanical Engineering, N.I.T KurukshetraJournal Article20100811In the present study, the boundary value problems in generalized thermodiffusive elastic medium has been investigated as a result of inclined load. The inclined load is assumed to be a linear combination of normal load and tangential load. Laplace transform with respect to time variable and Fourier transform with respect to space variable are applied to solve the problem. As an application of the approach, distributed sources and moving force have been taken. Expressions of displacement, stresses, temperature and concentration in the transformed domain are obtained by introducing potential functions. The numerical inversion technique is used to obtain the solution in the physical domain. Graphical representation due to the response of different sources and use of angle of inclination are shown. Some particular cases are also deduced.http://jsm.iau-arak.ac.ir/article_514390_3de3b085ee76139f2670c6323529b305.pdfIslamic Azad University - Arak BranchJournal of Solid Mechanics2008-35052420101230Wave Propagation at the Boundary Surface of Elastic Layer Overlaying a Thermoelastic Without Energy Dissipation Half-space363375514391ENRKumarDepartment of Mathematics, Kurukshetra UniversityVChawlaDepartment of Mathematics, Kurukshetra UniversityJournal Article20101007The present investigation is to study the surface wave propagation at imperfect boundary between an isotropic thermoelastic without energy dissipation half-space and an isotropic elastic layer of finite thickness. The penetration depth of longitudinal, transverse, and thermal waves has been obtained. The secular equation for surface waves in compact form is derived after developing the mathematical model. The components of temperature distribution, normal and tangential stress are computed at the interface and presented graphically. The effect of stiffness is shown on the resulting amplitudes and the effect of thermal is shown on the penetration depth of various waves. A particular case of interest is also deduced. Some special cases of interest are also deduced from the present investigation.http://jsm.iau-arak.ac.ir/article_514391_134ffbf8b8e4d41aa88957af24b521d0.pdfIslamic Azad University - Arak BranchJournal of Solid Mechanics2008-35052420101230Three-dimensional Free Vibration Analysis of a Transversely Isotropic Thermoelastic Diffusive Cylindrical Panel376392514392ENRKumarDepartment of Mathematics, Kurukshetra UniversityTKansalDepartment of Mathematics, Kurukshetra UniversityJournal Article20101004The present paper is aimed to study an exact analysis of the free vibrations of a simply supported, homogeneous, transversely isotropic, cylindrical panel based on three-dimensional generalized theories of thermoelastic diffusion. After applying the displacement potential functions in the basic governing equations of generalized thermoelastic diffusion, it is noticed that a purely transverse mode is independent of thermal and concentration fields and gets decoupled from the rest of motion. The equations for free vibration problem are reduced to four equations of second-order and one fourth-order ordinary differential equation after expanding the displacement potential, temperature change and concentration functions with an orthogonal series. The formal solution of this system of equations can be expressed by using modified Bessel function with complex arguments. The numerical results for lowest frequency have been obtained and presented graphically. The effect of diffusion on lowest frequency has also been presented graphically. Some special cases of secular equation are also discussed.http://jsm.iau-arak.ac.ir/article_514392_bc3c19ef40213bd8113a79e66eb8e4df.pdfIslamic Azad University - Arak BranchJournal of Solid Mechanics2008-35052420101231Wave Propagation in Sandwich Panel with Auxetic Core393402514393ENDQing-TianSchool of Science, Chang’an University, Xi’an, ChinaYZhi-ChunSchool of Aeronautics, Northwestern Polytechnical UniversityJournal Article20101221Auxetic cellular solids in the forms of honeycombs and foams have great potential in a diverse range of applications, including as core material in curved sandwich panel composite components, radome applications, directional pass band filters, adaptive and deployable structures, filters and sieves, seat cushion material, energy absorption components, viscoelastic damping materials and fastening devices etc.In this paper, the characteristic of wave propagation in sandwich panel with auxetic core is analyzed. A three-layer sandwich panel is considered which is discretized in the thickness direction by using semi-analytical finite element method. Wave propagation equations are obtained through some algebraic manipulation and applying standard finite element assembling procedures. The mechanical properties of auxetic core can be described by the geometric parameters of the unit cell and mechanical properties of the virgin core material. The characteristics of wave propagation in sandwich panel with conventional hexagonal honeycomb core and re-entrant auxetic core are discussed, and effects of panel thickness, geometric properties of unit cell on dispersive curves are also discussed. Variations of Poisson’s ratio and core density with inclined angle are presented.http://jsm.iau-arak.ac.ir/article_514393_5312e33c727d03f050f3cdae0cd14496.pdfIslamic Azad University - Arak BranchJournal of Solid Mechanics2008-35052420101231Two-dimensional Axisymmetric Electromechanical Response of Piezoelectric, Functionally Graded and Layered Composite Cylinders403417514394ENTKantInstitute Chair Professor, Department of Civil Engineering, Indian Institute of Technology BombayPDesaiManager (Design), S N Bhobe and Associates, Navi MumbaiJournal Article20101226A mixed semi-analytical cum numerical approach is presented in this paper which accounts for the coupled mechanical and electrical response of piezoelectric, functionally graded (FG) and layered composite hollow circular cylinders of finite length. Under axisymmetric mechanical and electrical loadings, the three-dimensional problem (3D) gets reduced to a two-dimensional (2D) plane strain problem of elasticity. The 2D problem is further simplified and reduced to a one-dimensional (1D) by assuming an analytical solution in longitudinal direction (z) in terms of Fourier series expansion which satisfies the simply (diaphragm) supported boundary conditions exactly at the two ends <em>z </em>= 0, <em>l</em>. Fundamental (basic) dependent variables are chosen in the radial direction (thickness coordinate) of the cylinder. The resulting mathematical model is cast in the form of first order simultaneous ordinary differential equations which are integrated through an effective numerical integration technique by first transforming the BVP into a set of initial value problems (IVPs). The cylinder is subjected to internal/external pressurized mechanical and an electrical loading. Finally, numerical results are obtained which govern the active and sensory response of piezoelectric and FG cylinders. Numerical results are compared for their accuracy with available results. New results of finite length cylinders are generated and presented for future reference.http://jsm.iau-arak.ac.ir/article_514394_8b7cc9986e1ed479beab4580296cba0d.pdf