Elastoplastic Buckling Analysis of Cylindrical Shells Using a Semi-AnalyticalFormulation

摘要

In this thesis, a semi-analytical formulation for the buckling analysis ofcircular cylindrical shells is described that takes into account the combined effects of initial geometric imperfections, elastoplastic material behavior and boundary conditions. The model is based on small strains-moderate rotations shell theory. The governing equations are formulated as a coupled set of first-order ordinary differential and algebraic equations. The basic variables in these equations are the variables that can be prescribed at the shell edges. The model described in this thesis is valid for cylinders with a multi-layer wall construction that may be loaded by axial compression, external pressure and/or torsion. The governing differential/algebraic equations are solved using Newton-type iteration methods. Separate equations are formulated for the bifurcation analysis of axisymmetric prebuckling states and an efficient solution method for the eigenvalue problem is described. The correctness of the formulation is checked by analyzing a number of elastic and elastoplastic buckling problems of perfect and imperfect shells.