پديد آورنده :
بابايي، حامد
عنوان :
تاثير مقياس اندازه كوچك بر كمانش و ارتعاشات نانو صفحات چهار ضلعي بر پايه تئوري الاستيسيته غير محلي و استفاده از روش گالركين
مقطع تحصيلي :
كارشناسي ارشد
محل تحصيل :
اصفهان: دانشگاه صنعتي اصفهان.دانشكده مكانيك
صفحه شمار :
نه، 77ص: مصور،نمودار
يادداشت :
ص.ع.به فارسي و انگليسي
استاد راهنما :
عليرضاشهيدي
استاد مشاور :
سعيد ضيايي راد
توصيفگر ها :
مقياس كوچك , ورقه هاي گرافيني
تاريخ نمايه سازي :
90/4/29
استاد داور :
محمد مهدي سعادت پور، حميد رضا ميردامادي
چكيده فارسي :
به فارسي وانگليسي قابل روئيت در نسخه ديجيتالي
چكيده انگليسي :
Small Scale Effects on the Buckling and Vibration of Quadrilateral Nanoplates Based on Nonlocal Elasticity Theory Uusing the Galerkin Method Hamed Babaei h babaei@me iut ac ir 2011 11 4 Department of Mechanical Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language FarsiSupervisor Alireza shahidi shahidi@cc iut ac ir AbstractThe elastic buckling and vibration of quadrilateral single layered graphene sheets SLGS and multi layeredgraphene sheets MLGS embedded in polymer matrix are studied employing nonlocal continuummechanics Although classical continuum elasticity is a scale free theory and cannot foretell the size effects however continuum modeling of nanostructures has gained ever broaden attention Using local theory forthe small size analysis leads to the over predicting results In order to capture the small scale effects innonlocal continuum theory it is assumed that the stress at a point depends on the strain at all points in thedomain This is contrary to the classical local continuum theory in which it is assumed that the stress at apoint is just a function of the strain at that point So the nonlocal theory contains information about longrange interactions between atoms and internal scale length Besides the nonlocal continuum theory basedmodels are physically reasonable from the atomistic viewpoint of lattice dynamics and molecular dynamics MD simulations Small scale effects are taken into consideration The principle of virtual work isemployed to derive the governing equations The Galerkin method in conjunction with the naturalcoordinates of the nanoplate is used as a basis for the analysis The straight sided quadrilateral domain ismapped into a square domain in the computational space using a four node element The discretizing andprogramming procedures are straightforward and easy The non dimensional buckling load and naturalfrequency of skew rhombic trapezoidal and rectangular nanoplates considering various geometricalparameters are obtained and for each case the effects of the small length scale are investigated For MLGSembedded in polymer matrix the dependence of small scale effect on thickness elastic modulus polymermatrix stiffness and interaction coefficient between two adjacent sheets is illustrated It is clearly observedthat number of layer effect is negligible for lower first two and three modes while it is significant forhigher modes Further it is found that decreasing effect of number of layer on small scale effect continues tospecific number of layer e g five layers for fifth mode and seven layers for seventh mode and thenfrequency ratio converges to value of it for lower modes It is shown that nonlocal effects are veryimportant in arbitrary quadrilateral graphene sheets and their inclusion results in smaller buckling loads Also the effects of geometrical parameters such as aspect ratio angle and mode number on the bucklingload decrease when scale coefficient increases for all arbitrary quadrilateral graphene sheets Thisphenomenon is attributed to the size effects KeywordsSmall scale buckling vibration quadrilateral graphene sheet nonlocal elasticity Galerkin method
استاد راهنما :
عليرضاشهيدي
استاد مشاور :
سعيد ضيايي راد
استاد داور :
محمد مهدي سعادت پور، حميد رضا ميردامادي
