Analysis Of Mechanical Properties Of Concrete Filled CFRP-Steel Tube Component

CFCST is a composite structure filled with concrete in steel tube and winded with sheet CFRP external, its mechanism principle is to use the confining role of external tube (cylinder) makes the concrete core in the tri-axial pressure, in order to enhance its axial carrying capacity. The CFCST structure has much more advantages in the mechanics performances and construction performances, increasing steel tube corrosion resistance, improving the FRP tube plastic issues, and reducing the material cost, is a promising structure. Therefore, the CFCST further studies will become a hot research field.The CFCST structure is formed from carbon fiber, steel and concrete, three non-uniform, non-linear materials, which becomes a research problem for analyzing its stress.For study the mechanical properties of these components, by dint of the solid mechanics theory, the analytical answer of the stress and deformation on CFRP component were derived by balance equation and deformation equations under conditions with the axial compression and pure bending load; proposing expression of the equivalent modulus of overall component; giving conditions of concrete confined and discussing the concrete tensile stress conditions of the eccentric component, then mechanical responses of several materials are given in the case of whether the concrete tensile stress occurring of the eccentric component.Comparing the theoretical results with experimental results, the correctness of the theoretical derivation formula is verified. Based on the theoretical formula derived load - strain curve is rendered, then analyzing the impact of the thickness of steel tube and CFRP layers on the ultimate bearing capacity and stiffness of the overall component by load - strain curve, giving the relationship between the thickness of tube and the occurrence time of tight force. The results show that this theory can be used as the basis of further study and the foundation of design and engineering calculation on CFRP concrete-filled steel tube structure. For the shortcomings of test specimen number insufficient, numerical simulations of axial compression and eccentric component are done on CFCST with ABAQUS, respectively. Comparing the load-strain curve of finite element analysis with the experimental curves, the results show that the establishment of the mechanical properties of the finite element model on CFCST components is feasible, comparing finite element calculation results with the theoretical results can verify the correctness of this theoretical formula.