Research On Inertia Effect Of Concrete Dynamic Tensile Strength And Numerical Simulation

Concrete is widely used as a widely used building material in buildings.Not only to withstand static loads but also to withstand dynamic loads by accident,Therefore,it is very important to study the influence of inertia on the strength of concrete under dynamic loading.?1?In this paper,the effects of inertial effect on the dynamic tensile strength of concrete are studied by the drop hammer strength test and numerical simulation.Complete the static test of the concrete and the related material test,The compressive strength and static tensile strength under static load as well as the elastic modulus and Poisson's ratio and material parameters were obtained.?2?The dynamic splitting tensile test of the control and test specimens with the strain rate range of 2S^-1-4S^-11 was completed by the drop weight tester.The force time history curve and the strain timehistory curve were recorded by measurement with the height and mass of the drop hammer as the variation parameters.The test results show that the peak load of the test group and the control group increases with the increases of the height or mass of the drop weight.There is no significant difference between the two groups of specimens.?3?The test used a high-speed camera to capture the crack development on the surface of the test piece during the impact process,and analyzed the test data results.As the mass or height of the drop weight increases,the peak load of the test group is slightly higher than that of the control group,the force time history curve and the strain time history curve are slightly advanced.There is no significant difference in the number of ultimate tensile strains betwee n the two groups;The damage of the test piece is changed from the breakage of the test piece to the crushing damage of the test piece as the height or mass of the drop weight increases.?4?The results of comparative analysis show that the inertia effect has a great influence on the dynamic tensile strength of concrete in the dynamic tensile test of concrete.In the dynamic tensile test of concrete,due to the large size of the test piece,the inertial effect is caused by the transition from One-dimensional stress damage to One-dimensional strain damage during the damage of the test piece;The coupling effect between the inertial effect and the confining pressure sensitivity of the concrete specimen inhibits the expansion of the concrete crack and ultimately leads to the improvement of the dynamic strength of the concrete.?5?The PFC2D discrete element software was used to simulate the drop hammer impact cracking of the experimental group and control group under different working conditions.The numerical simulation and test results were compared comprehensively from the force time history curve,the strain time history curve and the specimen damage phenomenon,and The feasibility of PFC discrete element software in analyzing dynamic tensile tests was verified.