Study On Structural Stressing States And Failure Criterion Of Steel Frame Structures

Steel frame, as a kind of common structure, with its clear load path and excellent mechanical property, is widely utilized in residences, office buildings, industrial plants,public buildings and so on. Present studies on steel frame failure are mainly based on the following criterions: the structure forming a variable system; overall deformation of structures exceeding the threshold; the load capacity of structures approaching the ultimate limit and so on. These guidelines in different situations have rationality and features respectively but all based on different definitions of failure, without unified decision basis.This paper is based on stressing state analysis theory of structure. first, simple steel beams and steel frame were taken as research objects. Then, we do static elastic and plastic analysis of the progressive loading on the models to supply data base for analysis of stressing state. Express different stressing state by increasing ratio of ESEND and establish ESEND numerical model to express stressing state of structure. At last build failure criterion and apply numerical analysis the influence of construction parameter and nonlinear. Specific work is as follows:First, analyze the rationality and feasibility of applying ESEND to analyze structure stressing state and build relative numerical model to express local stressing state.Then, establish ESEND numerical model to describe the whole mode stressing state of the structure, make prediction of failure load by the stress state of the ESEND and calculate stress distribution of local stressing state nearby failure of structure and validate failure load is the cut-off point of different stress state. In the light of the bending member, the boundary points are calculated, and compared with the predicted failure load,validity of the numerical model established in this paper.Make numerical mode of structural stressing state based on ESEND develop into failure criterion. Through numerical examples of the frame structure, confirm the applicability of the criterion; according to the example analysis of steel frame who have different span, section stiffness of steel beam and different failure modes, explore user-defined parameters ESEND development coefficient and structure failure and destruction of the corresponding modes; and the failure and other standards based on the ESEND were comparedAt last, preliminary inquiry of the failure reason of the bending members and frame structure and the influence of geometric nonlinear and material nonlinear factors were made. Impacts of the two common initial geometric imperfections for the influence of structural failure were analyzing clearly.