Computational modeling applied to the elastic buckling of columns

Abstract

Buckling is an instability phenomenon which occurs in slender structural members subjected to compressive load. The elastic buckling is characterized by a suddenly lateral deflection of the slender structural member, when the critical load is reached. In columns the elastic buckling is considered the collapse of the structure. The goal of this work is to present three different computational models to analyze the elastic buckling of columns. The software ANSYS, which is based on the Finite Element Method (FEM), was adopted to develop these models, employing the elements BEAM189, SHELL93 and SOLID45. The boundary conditions and compressive load must be applied in a specific way for each model, depending of the finite element characteristics. Different boundary conditions were considered for each numerical model. In the verification of these models, the analytical solutions for these boundary conditions were used. All the numerical results obtained are in agreement with the analytical ones, being the higher difference encountered of 2.83 %. Besides, the columns buckled shapes numerically obtained are also in agreement with the theoretical configurations. The advantage of the use of computational models developed with SHELL93 and SOLID45 finite elements is the possibility of analyzing columns with holes or with complex geometries.