Finite Element Analysis On Constitutive Model Of Reactive Powder Concrete Restrained By Circular Steel Tube

:Further research on constitutive relation of RPC (Reactive Powder Concrete, RPC) restrained by steel tube under axial compression are analyzed based on the research on concrete-filled steel tube and RPC-filled steel tube at home and abroad. Finite element analysis on some specimens is carried out with ABAQUS to get the influence factors on RPC-filled steel tube stub columns under axial compression. Finite element analysis on41specimens with ABAQUS is carried out to get the empirical formula of the peak stress, plateau stress and peak strain, and then get the formula of stress-strain curve. The main research results are as follows:(1) Constitutive model of the material of RPC-filled steel tube is introduced and reasonable steel constitutive models of steel and RPC are selected:steel model is used as double linear model in theory analysis, which is divided into the elastic segment and strengthening segment in the paragraph. Core concrete constitutive model is divided into rising, horizontal, drop and residual straight segment.(2) Finite element analysis on RPC-filled steel tube stub columns under axial compression is carried out with ABAQUS to analyze the confinement index, core concrete strength and contact property on bearing capacity of RPC restrained by steel tube.Bearing capacity of RPC restrained by steel tube is increased as the confinement index and the core concrete strength are increased. The model with frictionless contact form has better bearing capacity, but the ductility properties is decreased. The curve of restrained RPC with axial compression is divided into four stages; elastic stage, elastic-plastic stage, decline stage and flat stage.(3) The finite element model of41RPC-filled steel tube stub columns is established to get experiential formula of peak stress, plateau stress and peak strain on restrained RPC, and then the equation of stress-strain curve is established.This research has established constitutive model of restrained RPC constitutive model empirical formula which provides theory basis and reference for the future research.