NONLINEAR-ANALYSIS OF THIN-WALLED STRUCTURES USING LEAST ELEMENT MEMBER

The paper presents the derivation of a deformation stiffness matrix for an asymmetric thin-walled beam-column element. This matrix KD is a function of element deformation and incorporates the coupling between axial stretching and the lateral and torsional deformations. The stiffness matrix derived and the solution procedure proposed may be used together with the linear and geometric stiffness matrices for thin-walled beam-column elements to analyze large deflection behavior of space frames comprising members in which the influence of sectorial warping in the section can be neglected. These include members with solid, tubular hollow, or angle type sections. The formulation has been applied to a variety of sample problems involving arbitrarily large deflections. Results obtained from the approach using only one element per member in most cases agree very well with independent analytical and other published finite element solutions. The proposed method is suitable for analyzing the nonlinear behavior of large space frames, such as transmission towers. © ASCE.