Research On Collapse Of Welded Steel Frame Structures Considering Material Damage Failure

Steel structure has been considered to be the structure of superior seismic performance.However,according to information survey,such as the Great Hanshin Earthquake in Japan and the Northridge earthquake in California has led to a large number of steel structures collapsed and damaged,resulting in some incredible damage phenomena(such as posterior wall column brittle fracture,etc.),which leads to our thinking of the collapse mechanism of steel structure.Therefore,it is necessary to study structural collapse failure process and the collapse mechanism,to summarize the interstory displacement angle limit law of steel frame and to determine the reasonable damage index of whole structures.In view of the above problems,ABAQUS finite element analysis software is used to analyze the static pushover of plane steel frame.The research contents are as follows:1.In terms of material: Unit characteristic length is used to establish the equivalent plastic displacement and the equivalent plastic strain relations,defined by equivalent plastic displacement of material damage to the failure of the development process.This paper adopts linear failure development process;Simulatio n aspects: The birth and death unit technology and the explicit algorithm have been used to complete the numerical simulation of steel tension and compression experiment;To one common plane steel frame monotonic lateral pushover experiment,explicit and implicit numerical simulation have been done respectively and compared with the experimental data through the experiment phenomenon.The correctness and feasibility of the parameters of the explicit finite element model is verified.Determine the specific parameters for further analysis of structure collapse.2.The design of a plane steel frame using PKPM and monotonic lateral pushover analysis has been conducted.Set the action point of the reaction force as 0 when the structure is at the collapse of the critical limit and validate the correction of the definition;The collapse structure failure process is divided into five stages;Analysis of the failure process and damage reason from structures to components has been done;The mechanism of structure collapse has been summarized;The development and limit of the interstory displacement angle has been discussed;The damage index of ductility—stiffness degeneration has been put forward.3.On the basis of the original steel frame model,by changing the model span,layer height and separately strengthening the beam,column and node,the structures are analyzed by pushover.The collapse damage mode of the structures,the change law of the interstory displacement angle and the accuracy of the damage index for damage development after the change of the structure have been studied.