Consistent formulations for geometric nonlinear analysis of space framed structures

Abstract

This paper is concerned with the geometric nonlinear and buckling analyses of space framed structures emphasizing how to model the effects of geometric nonlinearity consistently. Two consistent formulations are presented in this study; one is on the basis of small rotation, while the other large rotation. The consistency makes the derived element and structural tangent stiffness matrices symmetric. Although the tangent stiffness matrices are different, these two formulations predict the same nonlinear responses and buckling loads. It is also shown in this paper that the incremental equilibrium equations for these two formulations are equivalent to those derived by Yang and Kuo (1994). However, the element tangent stiffness matrix in Yang and Kuo (1994) is asymmetric.