Finite Element Analysis Of Axial Compression Short Column Of Active Powder Concrete With Round Steel Tube

The existing research on concrete filled steel tube and reactive powder concrete,on the basis of core of reactive powder concrete filled steel tube column has carried on the theoretical research,analyzes the total cross-section under axial compression loading combination column mechanical properties,and is simulated by using large-scale finite element analysis software ANSYS,to explore the work principle of two kinds of materials.At the same time,the formula for calculating RPC ultimate bearing capacity of steel pipe is obtained by fitting the ultimate bearing capacity obtained from simulation.The main research results are as follows:1.Combining several groups of test data,the calculation formulas of peak strain and peak stress of unconstrained RPC column were proposed.The relationship between mechanical behavior of core concrete and plain concrete under steel tube constraint was explored,and the calculation formulas of characteristic points of stress-strain curve of core RPC column under steel tube constraint were obtained.2.The working principle of the peel analysis method is introduced,and the ascending and descending sections of the stress-strain curve of the core concrete in the compression process are extracted respectively.The curve data are analyzed,and the constitutive curve of the core RPC column under the constraint of steel pipe is obtained by modification on the basis of the Han Linhai constitutive model.3.The nonlinear finite element model was established by using the analysis software ANSYS,and the accuracy of the model was verified by comparing with the test data.The mechanical behavior of steel tube and concrete in each stage of loading process was analyzed,and the cooperative working principle of composite column was further understood.4.The influence of steel pipe length-diameter ratio,yield strength and compressive strength of core concrete on composite axial compression column is explored,and the influence factors of peak strain and peak stress of composite column are discussed,and the change of specimen stress-strain curve caused by the size of collar index is analyzed.5.By comparing the existing codes at home and abroad,it is found through calculation that the ultimate bearing capacity formula of ordinary CFST given in most codes is not applicable to RPC of steel tube.Based on the limit equilibrium theory,the expression of the ultimate bearing capacity of RPC of steel pipe was deduced.By fitting the data obtained from the previous finite element simulation,the formula of the ultimate bearing capacity of RPC of steel pipe was obtained.At the same time,a large number of test data were collected,and the correctness and universality of the formula were verified by calculation.