تحليل رفتار پس كمانش ورق هاي دايرويFGMتحت بارهاي داخل صفحه اي وجانبي

چكيده انگليسي :

Post Buckling Analysis of Functionally Graded Circular Plates under In plane and Transverse Loading Mohammad Vahidi Poor mk vahidipoor@me iut ac ir Date of Submission 2012 5 3 Department of Mechanical Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language FarsiSupervisor Ali Reza Shahidi shahidi@cc iut ac irSupervisor Hasan Khademizadeh khademizadeh@cc iut ac irAbstract Functionally graded materials FGMs have received considerable attention in many engineeringapplications since they were 4rst reported in 1984 in Japan see Koizumi 1993 FGMs are compositematerials microscopically inhomogeneous in which the mechanical properties vary smoothly and continuouslyfrom one surface to the other in one or more direction s This is achieved by gradually varying the volumefraction of the constituent materials FGMs were initially designed as thermal barrier materials for aerospacestructural applications and fusion reactors FGMs are now developed for general use as structural components inextremely high temperature environments Unlike 4ber matrix composites which have a mismatch ofmechanical properties across an interface of two discrete materials bonded together and may result in debondingat high temperatures FGMs have the advantage of being able to withstand high temperature environments whilemaintaining their structural integrity Thus FGMs are finding applications in many fields such as aerospace power generation industries and energy conversion With the increased usage of these materials it is importantto understand the buckling and post buckling behaviors of functionally graded circular plates Circular platesmade of functionally graded materials are often employed as a part of engineering structures Studies on FGcircular plates are however rare in comparison with those available on FG rectangular plates Most widelyknown type of FGM is a combination of metal and a refractory ceramic An axisymmetric and asymmetric postbuckling analysis is presented for a functionally graded circular plate subjected to in plane and transversemechanical loading Material properties are assumed to be graded in the thickness direction according to asimple power law distribution in terms of the volume fractions of the constituents The governing equations of afunctionally graded circular plate are based on the first order shear deformation plate theory with von Karmannon linearity Introducing a stress function and a potential function the governing equations are uncoupled toform equations describing the interior and edge zone problems of FG plates This uncoupling is then used toconveniently present an analytical solution for the non linear axisymmetric and asymmetric post buckling of anFG circular plate A perturbation technique in conjunction with Fourier series method to model the problemasymmetries is used to obtain the solution for clamped and simply supported boundary conditions The resultsare verified in four cases by comparison with the existing results in the literature For the purpose of numericalillustrations two material systems of FGM aluminum zirconia and aluminum alumina will be considered Theeffects of material properties boundary conditions and boundary layer phenomena on various responsequantities in a solid circular plate are studied and discussed It is observed that the boundary layer width isapproximately equal to the plate thickness with the boundary layer effect in simply supported FG plates beingstronger than that in clamped plates It is found that unlike simply supported FG plates the bifurcationphenomenon exists in clamped plates Results also show that the amounts of the radial stress resultant in FGplates lie between those of a fully metallic plate and a ceramic plate for all edge supports Keywords Functionally graded material Post buckling Perturbation Bifurcation Potential function

وحيدي پور، محمدكاظم

تحليل رفتار پس كمانش ورق هاي دايرويFGMتحت بارهاي داخل صفحه اي وجانبي

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