Study On Mechanical Properties And Constitutive Relations Of Concrete Impacted By Impact

As an important transportation facility,the safety performance of bridges is the focus of attention.With the increasing number of accidents caused by super-high vehicles hitting the superstructure of bridges,people are increasingly concerned about the impact of bridges in the face of loads such as explosions,impacts,and collisions.Safety performance.When the impact force is small,although the overall structure of the bridge will not collapse,it still has a certain bearing capacity,but the structure has internal damage and needs to evaluate its bearing capacity;when the impact force is large,the bridge may have local damage,but is It is imperative to push down reconstruction and also to make decisions.Therefore,it is very important to study the mechanical properties of concrete after impact,and to understand the mechanical properties of the affected concrete and evaluate the bearing capacity of the bridge under impact.In this paper,the theoretical and experimental researches on the mechanical properties after concrete impact are carried out.The high-performance drop hammer tester is used to impact the concrete specimens,and different impact forces(mild and heavy)are applied to the concrete,and the simulation calculations are performed.Then the pressure is 2000 KN.The machine was subjected to a uniaxial compression test to obtain stress-strain curves and mechanical properties of the concrete after impact.At the same time,using ANSYS/LS-DYNA software to simulate and calculate the drop-weight impact test,and compared with the test,to verify the reliability of the calculation method.The main work of this article is as follows:(1)Conduct theoretical analysis and simulation calculation of concrete impact test;(2)Carry out concrete impact test and use the impact stress level as a parameter to change the fall height by fixing the weight of the hammer to achieve an impact stress level of 0.5f_cu^imp and an impact stress level of 0.75f_cu^imp.During the impact process,the dynamic response of the falling hammer's impact force and concrete strain is measured and compared with the results of the simulation calculation.(3)Conduct the mechanical performance test of the concrete after impact,and study the mechanical properties and constitutive relations of the affected concrete.