Finite Element Analysis For Space Steel Frame With Semi-rigid Connections

Mufti-storied or high-rise steel framed structures are in the ascendant as an important structural system. Conventional analysis and design of steel frame structures are performed using the assumption that the connections are either fully rigid or ideally pinned. However, the connections in practice fall between the two extreme cases of fully rigid and ideally pinned. They are connections. This assumption of connections makes errors of calculating results and gets incorrect conclusions. Nonlinear finite element analysis for space steel frames with semi-rigid connections was performed in this paper.Development of space steel framed structures, current research of global steel framed structures, existing problems. After studying current advanced analysis theory of rigid and semi-rigid steel frames home and abroad, the stiffness matrixes for semi-rigid space steel frame were derived based on the finite-deformation theory of continuum mechanics and stress-resultant yield surface plastic rule by using Kishi-Chen power model to describe the nonlinear behavior of semi-rigid connections. They considered the combined nonlinear influences of semi-rigid connections, second-order, material and shear deformation on the behavior and strength of semi-rigid frames.Based on the feasibility verification about using spring element model with stiffness variation of double direction and the finite element software of ANSYS to analyze the test of Kim steel frames with two-story and one-bay , mufti-storied and high-rise space steel frames with semi-rigid connections are modeled. According to the counting of steel frames models which are six and twelve stories with different connectional forms, analyzing the effect of joint stiffness to the apical displacement and internal force of bean and column; according to the nonlinear counting of eight space steel frames models with different floors and joint stiffness, analyzing the effect of lateral joint stiffness to the apical displacement and internal force of bean and column.Results indicate that: to different bean-column connectional space steel frames, the change of joint stiffness should induce the change of displacement which would make the internal force of bean and column magnified. The effect of lateral joint stiffness to displacement of space steel frames is nonlinear which is greater in special area and rising as the increasing of height, the effect should not be ignored.