بررسي پايداري ارتجاعي و غير ارتجاعي صفحات مايل به روش نوار محدود اسپيلاينElastic and inelastic local buckling analysis of skew plastes by Spline Finite Strip Method

چكيده انگليسي :

Elastic and inelastic local buckling analysis of skew plates by Spline Finite Strip Method Shahram Lotfi Mahiary s lotfimahiary@cv iut ac ir July 13 2010 Department of Civil Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree MS c Language Farsi Mojtaba Azhari mojtaba@cc iut ac ir Abstract Plates are two dimensional structural elements with flat or bent geometries and having a widespread industrial use They can be formed easily in different shapes to make less heavy structures and more economic benefits Thin plates with different shapes are used in constructing ships automobiles buildings and so on So plate stability under compression is being noticed by experts As exact solution of partial differential equation for plate buckling analysis is difficult numerical solutions are used widely to solve these equations today The semi analytical finite strip method of structural analysis has proven to be both accurate and efficient for analysing the buckling of structural members and stiffened plates It is know convenient to introduce three types of finite strip method of structural analysis such as ordinary complex and spline finite strip method The spline finite strip method was developed from the semi analytical finite strip method originally derived by Cheung The finite strip method was based on harmonic functions and proved to be an efficient tool for analyzing structures with constant geometrical properties along a particular direction generally the longitudinal one The spline finite strip method complemented the finite strip method by allowing more complex types of loading and geometry to be modeled at the expense of a more comprehensive set of displacement functions based on splines Using spline finite strip method to analyse the plate buckling even considering less degrees of freedom comparing finite element method better results may attained and also this method converges faster to the answer In this thesis the local buckling of skew plates is studied The general theory of the spline finite strip method is introduced The kinematics assumptions strain displacement and constitutive relations of the Kirchhoff hypothesis in thin plates are described and applied to the spline finite strip method The corresponding matrix formulation is utilized in the equilibrium and stability equations to derive the stiffness and stability matrices Using spline finite strip method the elastic and inelastic local buckling of skew plates with different end conditions and subjected to in plane stresses are studied and the initial local buckling coefficient of such plates were obtained In the same way the local buckling of simply supported quadrilateral tapered plates in both elastic and inelastic range of response and subjected to in plane stresses has been studied too and the local buckling coefficient of such plates are obtained too A number of numerical examples of skew plates illustrate the applicability and accuracy of the proposed method Plate thickness reduction in some parts of structure which does not have a striking effect on the buckling coefficient let a lighter and more economic design It could be used in construction of body and wings of airplanes to increase their efficiency in high speed It could also be used to decrease the weight of slabs in roofs and bridges Key words plate buckling inelastic spline finite strip

لطفي مهياري، شهرام

بررسي پايداري ارتجاعي و غير ارتجاعي صفحات مايل به روش نوار محدود اسپيلاينElastic and inelastic local buckling analysis of skew plastes by Spline Finite Strip Method

كمانش