13763

12513

كارشناسي ارشد

طراحي كاربردي

اصفهان: دانشگاه صنعتي اصفهان، دانشكده مكانيك

۱۳۹۷

يازده، ۵۹ص.: مصور، جدول، نمودار

مهدي سلماني تهراني

عليرضا شهيدي

محمد مشايخي، رضا جعفري ندوشن

1397/05/27

كتابنامه

مكانيك

مهندسي مكانيك

ID12513

Elastic Plastic Buckling of a Rectangular Plate with Variable Thickness and Orthotropic Anisotropy Mohammad Moein Javadi mm javadi@me iut ac ir Date of Submission 2018 6 27 Department of Mechanical Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language FarsiSupervisor Mehdi Salmani Tehrani tehrani@cc iut ac irAbstractNowadays plates and shells are widely used in various engineering applications such as shipbuilding bridgesand aerospace industries Plates are usually under in plane uniaxial or biaxial compressive edge tractionwhich may result in buckling failure Therefore studying the buckling capacity or buckling strength of platesis one of the most important subjects in the designing procedure of a plate structure On the other hand theplates which are produced by cold rolling process are inherently anisotropic due to preferred orientation ormechanical fibering which in turn may be resulted from the alignment of any impurities Henceforth it is anatural question that how does the anisotropy characteristics affects the buckling capacity of a plate structure The present thesis aims at the investigation of elastic plastic buckling of a rectangular orthotropic thick plate with variable thickness under uniform uniaxial or biaxial compressive edge traction Two types of simplysupported and clamped boundary conditions were considered for the plate edges In order to model the plasticbehavior of plate both of the incremental and deformation plasticity theories were used Also the mostnovelty of this study was the change in the thickness of the plate according to the length of it so that thicknesschanges as a linear function of length Ramberg Osgood equation was assumed for the uniaxial stress straincurve of plate to obtain material constants The critical buckling traction was determined based on the integralcriterion of uniqueness of solution To this end polynomial Rayleigh Ritz method was used to approximatethe transversal deflection and rotations degrees of freedom of plate Substituting the approximate functionsinto the integral criterion and then minimizing the integral in terms of the polynomial unknown coefficientsresults in a homogeneous system of equations In order to obtain the non trivial solution the determinant ofthe matrix of the coefficients should be equal to zero Therefore a nonlinear algebraic equation is obtained The critical buckling traction is calculated as the lowest root of the equation In order to verify the analysis it was shown that as the polynomial order is increased the results are converged Then the critical bucklingload for a thick isotropic rectangular plate with uniform thickness under equi biaxial loading and simplysupported boundary conditions were calculated and compared with previously published results A very closeagreement was observed which evidently shows the validity of the analyses Finally the effect of anisotropiccoefficients the slope of thickness variation and the aspect ratio of the plate on the critical buckling load wasstudied Keywords Elastic Plastic Buckling Rectangular Plate Hill 48 Plastic Anisotropy Variable Thickness Strength and Potential Energy Rayligh Ritz Method

مهدي سلماني تهراني

عليرضا شهيدي

محمد مشايخي، رضا جعفري ندوشن