Effect Of Fatigue Damage On Dynamic Tensile Properties Of Reinforcement And Dynamic Bond Properties Between Reinforcement And Concrete

Reinforced concrete structures are widely used in practical engineering,and due to the frequent explosions in recent decades,more and more scholars have carried out research on the mechanical properties of reinforced concrete structures under blast impact loads.The dynamic mechanical properties of steel reinforcement and its dynamic bonding properties with concrete have been the focus of research,both of which play an important role in the strength and overall stability of reinforced concrete structures.In this paper,the dynamic tensile properties of reinforcing steel and the dynamic bonding properties of reinforced concrete are studied considering the repetitive loading during long-term service,i.e.,the effect of fatigue damage on the dynamic tensile properties of reinforcing steel and its dynamic bonding properties with concrete can accurately reflect the dynamic mechanical response of reinforcing steel tensile and bonding between reinforcing steel and concrete in actual engineering.The main research contents are as follows:(1)The effects of different fatigue damage on the static mechanical properties of reinforcing bars were investigated by applying repeated loads with different stress levels and number of cycles to the bars,and the changes of yield strength,ultimate strength and modulus of elasticity of the bars under the action of fatigue load were obtained,and the logarithm of the strength of the bars was linearly related to the strain rate through the dynamic tensile test of the bars,and the empirical equations of the increase coefficient of yield strength and the increase coefficient of ultimate strength of the bars with the change of strain rate were studied,and then the influence law of fatigue damage on the increase coefficient of ultimate strength of the bars was analyzed.(2)Repeated loads with different stress levels and number of cycles were applied to the reinforced concrete bonded specimens,and the empirical equations to quantify the fatigue damage of reinforced concrete bond were obtained from the test results.The experimental study of the bonding performance of reinforced concrete under impact loading was conducted to obtain the linear relationship between the dynamic increase coefficient of bond strength and the loading rate,and to give the empirical formula for the change of the increase coefficient of bond strength of reinforced concrete with the loading rate under different degrees of damage by studying the influence of different fatigue damage on the static and dynamic bond-slip intrinsic relationship between reinforcing steel and concrete,and to analyze the influence of fatigue damage on the The effect of fatigue damage on the bond strength increase coefficient between reinforcement and concrete under different loading rates is analyzed.By studying the influence of fatigue damage on the dynamic tensile property of reinforcement and the bond property between reinforcement and concrete,this paper can more accurately reflect the mechanical response of existing structures under impact load,providing a more accurate material model for the anti-explosion analysis of structures in the future ulation of the dynamic mechanical properties of such members in the future.