Stability Analysis Of CFRP Circular Concrete Filled Steel Tubular Columns Under Axial Compression

The service life of concrete-filled steel tube is determined by steel tube corrosion and local buckling of steel tube.The research shows that the good corrosion resistance of CFRP can protect the steel tube,and the large tensile strength can limit the local buckling of steel tube.In practical engineering applications,members with large slenderness ratio have a high utilization rate.In addition to the material strength and the interaction between different materials,the ultimate bearing capacity of members can be determined,and the stability performance also plays a decisive role.Therefore,it is very necessary to study the stability of CFRP concrete-filled steel tubular medium and long columns under axial compression.In this paper,four groups of axial compression stability experiments of CFRP concrete-filled steel tubular medium and long columns are collected and summarized.Combined with the ultimate bearing capacity formula of CFRP concrete-filled steel tubular short columns proposed in other literature and the stable bearing capacity formula in the modified concrete-filled steel tubular code,the stable bearing capacity formula of CFRP concrete-filled steel tubular is obtained,which is in good agreement with the experimental data in other literature.Based on the stability bearing capacity formula of CFRP concrete-filled steel tubular column proposed in this paper,the weakening coefficient is added,and the stability bearing capacity formula of CFRP concrete-filled steel tubular column considering CFRP winding angle is obtained.The ANSYS finite element model of all materials of the test piece is established by using 18 x series elements,and has passed the data verification.Based on the experiments in other literatures,the height of the specimen is re divided according to the regular slenderness ratio,and the finite element results are in good agreement with the theoretical results.The load deflection curve and stress nephogram obtained by finite element analysis are analyzed.At the same time,CFRP concrete-filled steel tubular short column,medium long column and long column are re divided according to the regular slenderness ratio.The material parameters of CFRP finite element are reset to establish the finite element model of CFRP concrete filled steel tubular considering the winding angle of CFRP.The finite element results are in good agreement with the theoretical formula proposed in this paper.It is analyzed that the CFRP enhancement coefficient decreases with the increase of winding angle.The reinforcement coefficient of CFRP decreases with the increase of slenderness ratio.