بررسي كمانش مكانيكي و حرارتي و ارتعاش آزاد ورق هاي ناهمسان در ضخامت بر روي بستر ارتجاعي با استفاده از روش نوار محدود

چكيده انگليسي :

Thermal and mechanical buckling and free vibration of thick functionally graded plate resting on elastic foundation using the finite strip method Hamid Foroughi h foroughi@cv iut ac ir Date of Submission 2013 02 22 Department of Civil Engineering IsfahanUniversity of Technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi Supervisor Prof Mojtaba Azhari Mojtaba@cc iut ac ir Advisor Prof Bijan Boroomand boroomand@cc iut ac ir Abstract In this thesis free vibration and buckling of thick rectangular plates made of functionally graded material FGM under various types of mechanical and thermal loading is considered It is assumed that the plate resting on elastic foundation during deformation The derivation of equations is based on the third order shear deformation theory TSDT Functionally graded materials FGM are advanced composites that are designed to tolerate high stresses especially high temperature gradients It is assumed that FGM plates have two fuully ceramic and metal surfaces Ceramic supplies high thermal resistance while metal provides high stiffness and ductility The mechanical non homogeneous properties of FGM plate vary smoothly by distribution of power law across the plate thickness while the poison s ratio is supposed to be constant The elastic foundation is modeled by Winkler and two parameters Pasternak model Most researches have simulated the behavior of elastic foundation using only normal stresses based on a model developed by Winkler In this simplified model a proportional interaction between pressure and deflection of plate and elastic foundation is assumed which is carried out in the form of discrete and independent vertical springs Pasternak model suggested considering not only the normal stresses but also the transverse shear deformation and continuity among the spring elements and its subsequent applications for developing the model for buckling and free vibration analysis proved to be more accurate than Winkler model The fundamental equations for rectangular plates of functionally graded material FGM resting on elastic foundation are obtained by discretizing the plate into some finite strips The solution is obtained by the minimization of the total potential energy and solving the corresponding eigenvalue problem The governing equations are solved for FGM plates under the free vibration and mechanical and thermal loadings separately In mechanical buckling two types of uniaxial and biaxial loading are obtained and discussed In the same way free vibration of FGM plates resting on elastic foundation is considered and free vibration frequencies are drived and compared with other similar researches In thermal buckling Three types of thermal loadings uniform temperature rise linear temperature change across the thickness and nonlinear temperature change across the thickness are considered and the buckling temperature difference are derived In addition numerical results for a variety of functionally graded plates with different boundary conditions are presented and compared with those available in the literature and free vibration are determined and discussed Keywords Mechanical buckling Thermal buckling Free vibration Thick functionally graded plate Elastic foundation Finite strip method PDF created with pdfFactory trial version www pdffactory com

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بررسي كمانش مكانيكي و حرارتي و ارتعاش آزاد ورق هاي ناهمسان در ضخامت بر روي بستر ارتجاعي با استفاده از روش نوار محدود

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