Reserch Of Damage Model Of Concrete-filled Steel Tube Under Simulant Earthquake Forces

Buildings under earthquake will be with varying degrees of damage and destruction, but the damage and the destruction are not one time to complete. Usually, they are the cumulative result of structural damage caused to a certain degree. Because of economic and security reasons, structure engineers must follow the seismic design of buildings ------"earthquake does not collapse, the shock can repair, minor earthquake" principle, which called for the structure under earthquake, allowing the damage to some extent. Cumulative damage of the structure of the building will no doubt be an important impact on the follow-up period of resistance and the residual life. However, the complexity of the issue and the limitations of human knowledge, so far, in term of CFT (concrete filled steel tubular ) frame for seismic design of structures, people have been with little consideration to the impact of structural cumulative damage. Thus, under the earthquake consider effects of cumulative damage of CFT column could improve the capacity of CFT frame structure and give full play to its mechanical properties, all of these have a great significance.CFT framework structure is a new structural system, with its good seismic performance, high load capacity, a significant economic advantages, such as high-level of load and long-span structures, which are more and more applications. However, a long time, for the research of CFT only focused on the mechanical properties of components and frameworks for their own overall performance, few of the CFT Component Damage under earthquake force and even fewer on Seismic Damage Model of CFT columns .The damage model of CFT columns is one of the important foundations to reasonably institute the yield mechanism of CFT overall framework .The subject combines the computer simulation and experiment to extract damage model of CFT columns under seismic force , to fit damage parameters, and to determine the damage formula, and finally to grasp the damage status of CFT columns under cyclic loading , then,we could create the good foundation to develop reasonably the failure mechanism of CFT Frames.Taking into account the universal of CFT damage model, this article summarizes a lot of existing researchs in this area, based on the finite element software abaqus, combined the relevant experiment, simulates and analysises the effects of different controlling parameters to the CFT damage model, For example: increase thickness ratio (D/t), slenderness ratio (λ), axial compression ratio(n), loading methods and so on, and realizes the relationship among the yield displacement and the cumulative displacement of CFT column and yield energy and accumulation of yield energy, which determine the damage parametersα,β.If the damage model of CFT columns under earthquakes is established, we could ensure the stress state of the CFT components , which provides a theoretical guarantee for the greater use of CFT seismic performance and the mechanical properties , so that frame design is more secure, economic and reasonable, which are more important academic significance and potential applications.