A Non-linear Constitutive Model Of Steel Fiber Reinforced Concrete Based On Fiber Orientation Distribution

Concrete is a sort of construction material which has some advantages like high compressive strength.However,it has some drawbacks such as low tensile strength and easy cracking.To remedy the defects of concrete,many kinds of reinforced concrete have been widely applied in all kinds of fields of civil engineering like steel fiber reinforced concrete.Mechanical performance and constitutive relationships of SFRC are considered as a foundation of its application,which are considerably beneficial to engineering construction.Therefore,the study of constitutive relation of SFRC is the focus of this paper.In this paper,firstly the four-point bending test of SFRC beam(550mm×150mm×150mm)is done.According to the test,the relevant four-point test will be simulated with the finite element software ABAQUS.In the process of modeling,the constitutive relation of SFRC is studied deeply.As the steel fibers are not distributed uniformly through the whole beam,the whole beam would be divided into blocks according to RVE method firstly,which can ensure a relatively uniform fiber distribution in each volume element.And then the elastic constitutive relation of each volume element would be settled.Because in the loading process,the steel fibers have always been in the elastic state before they are pulled out.On the contrary,the concrete has both elastic deformation and plastic deformation.So for the study of constitutive relationship of SFRC,the orthotropic elastic constitutive relation is adopted in the simulation of SFRC constitutive relationship.And the damage plastic constitutive model is used in the simulation of concrete constitutive relation.In addition,the fiber distribution has a big impact on the properties of SFRC.In order to make full use of the information of fiber orientation,the orthotropic elastic constitutive relation of fibers will be obtained with the method of fiber orientation tensor and the orientation distribution function.Finally,the experimental result will be compared with the numerical simulation result in terms of force-deflection curves and cracks,which verifies the validity and soundness of the constitutive model of SFRC.Meanwhile,the numerical results of concrete and the SFRC are compared to illustrate how the fibers affect the properties of concrete.In order to explore the factors influencing the mechanical properties of SFRC,the variable parameter analysis on SFRC will be conducted.The variable parameters contain the fiber length and the fiber volume fraction.The related conclusions have a certain guidance and reference significance for the application of SFRC.