Dynamic Response Of Concrete-filled CFRP Square Steel Tubular Columns Subjected To Blast Loading

Frequent explosions have constantly threatened people’s lives and property. Then, How to improve the level of the blast prevention and protection for the structure has become an important and realistic topic. Concrete-filled CFRP-steel tubular column is being a new kind type of composite structure which has a better prospect for development and has rised gradually both in China and overseas for its not only have obvious merits, such as high strength, good ductility, better seismic behavior, and convenient construction but also can effectively delaying the buckling, steel can improve the bearing capacity and durability of concrete filled steel tube to make up for the shortage of ductility. At present the research of concrete-filled CFRP-steel tubular columns is focuses on the static aspect but the research of its dynamic performance is still very rare. This article combining the method of theoretical analysis and numerical analysis to analysis the dynamic displacements of concrete-filled CFRP-square steel tubular columns. It mainly includes the aspects show as following.(1) Based on two-parameter unified strength theory, the ultimate bearing capacity of hollow round concrete-filled CFRP-square steel tubular columns was analyzed. Using uniform restraint coefficient and lateral pressure coefficient, the performance of regular polygon cross section was analyzed by converted to circular cross section. Then, a unified ultimate bearing capacity solution for concrete-filled CFRP-square steel tubular columns under axial compression is proposed. Verified the correctness by comparison with literature test results, the influencing factors of formula is also discussed.(2) The combination stiffness of concrete-filled CFRP-square steel tubular columns is infered by CFST unified theory and the results of this paper. And the plastic limit bending moment of them were infered also. The maximum dynamic displacements were sloved on the basis of equivalentsingle-degree-of-freedom system through simplifing the explosive load as triangle impact load.(3) The models of concrete-filled CFRP-square steel tubular columns were built by using ANSYS/LS-DYNA. The validity of the models were proved by the comparison between the results of numerical analysis and that of the numerical models. The influences of the thickness of the CFRP, the strength grade level of the materials, the steel ratio, the axial compression ratio, the height of the column and the proportion distance were analyzed by changing the parameter of the model and the explosive load.