Buckling Analysis of Thin Sections using the Finite Strip Method with a Coupled Stiffness Matrix

Abstract

It is well known that thin-walled structures, when subjected to compression load, are susceptible to local buckling. Because of this, determining their strength often involves considering post-buckled states. The finite strip method using flat shell strips is ideally suited for the stability analysis of multiple-plate systems because of its ability to deal with a variety of different situations and also because of the small number of unknowns involved. For linear stability, a method has been developed for determining the initial stress matrices and bifurcation loads. In linear theory, it takes advantage of the orthogonality properties of harmonic functions in the stiffness matrix formulation to yield a block diagonal stiffness matrix. This method is also one of the many that can be applied in solving non-linear plate-structure problems. In recent studies it has been developed to predict the geometrically non-linear response of folded plate structures. In these works the analyses have been based on the use of theory where an alternative formulation leads to uncoupled solutions. However, in the case of geometric stiffness matrix calculation, the integral expressions contain the products of trigonometric functions with higher-order exponents and here the orthogonality characteristics are no longer valid. All the terms of the series are thus coupled. Therefore, the only possible way to form the stiffness matrix is the one which takes into account all of the series. It is the object of the present paper to extend and evaluate its application to the analysis of the problem of post-buckling of plate structures which have diaphragm ends and are subjected to compression load. © Civil-Comp Press, 2009.