Study On Fatigue Properties Of Steel Fiber Reinforced Concrete Under Uniaxial And Multi-axis Stress State

The widespread use of concrete materials benefited from the emergence of Portland cement in the 1920 s,and as a new type of building material,due to its convenient handling,low cost,durable and so on,making this material in the world of civil engineering widely used.Although the concrete has a good compression performance,but its tensile strength is only less than 10% of its compressive strength,making the concrete material can not be used for larger structures.In order to make concrete in a more complex environment to play a role,so in the concrete mixed with steel fiber to solve this problem.The appearance of steel fiber concrete not only solves the problem of low tensile strength of concrete,but also gives new properties such as longer fatigue life of concrete,maximizes its use,saves the cost,improves the safety and stability of the structure.In this paper,the steel fiber reinforced concrete is used as the research object,and the uniaxial cyclic loading test and the multi-axial compressive fatigue test are the main contents.The steel fiber incorporation rate,the magnitude of the stress amplitude and the change of the lateral pressure are used as variables.Fatigue properties of fiber reinforced concrete.At the same time,the finite element software Midas fea is used to simulate the simulation,and two test processes and results are simulated in the computer.The software analysis data are compared with the experimental data to obtain the conclusion of the fatigue performance of the steel fiber concrete.Fatigue life of steel fiber reinforced concrete specimen.First,the production of steel fiber reinforced concrete test block,do uniaxial tensile fatigue test,through the test to collect and sort out the data,make S-N curve,and use Matlab to do the polynomial fitting data to get the different steel fiber under the stress and life relationship.Second,with the same specifications of the test block,the same degree of incorporation in the case of multi-axis lateral pressure fatigue test,the different side of the steel fiber reinforced concrete fatigue life value.The influence of side pressure on the life of steel fiber concrete was found and analyzed.Finally,Midas fea finite element software was used to simulate and analyze the above two experiments.The process of loading the whole experiment was simulated and the remaining life and damage were calculated and compared with the experimental data.