Experimental Study On Dynamic Flexural-tensile Mechanical Behavior Of Concrete At Different Strain Rates

Concrete materials plays more and more important role in the use of modern buildingmaterials，they are one of the mostly used construction materials which are widly used inbuilding, raod, bridge, tunnel and so on. As composite material, the concrete materialscomes from dynamic loading which based on loading history in actual work environment,properties of concrete will be affected by the loading history. Relative to the staticmechanical properties of concrete, the dynamic mechanical properties of concrete materialsare more complex, in the work process of concrete subject to earthquakes, wind loads, andother loads blast loads, resulting in much closer to its actual stress situation, so concretedynamic mechanical properties of the security and stability of the structure plays a key role.The equipment and methods will affect the test results. So, in this paper, there is adynamic bending tensile test on the different intensity levels of concrete specimens on thebasis of summarizing the previous research results, using the MTS loading devices andadvanced data acquisition instrument, adopting the appropriate methods of makingspecimen and loading process.In this paper, there are dynamic bending tensile test on the different strength gradesconcrete specimens, and the dynamic bending tensile experiment was carried out usingdifferent strain rates, such as10-6/s、10-5/s、10-4/s. Strain rates and load histories and gradedloading make a large impact on dynamic bending tensile performance and deformationperformance of the concrete, including the bending tensile strength and modulus ofelasticity.Based on the damage theory, considering the strain rate strengthening effect anddamage weakening effect in this paper, the dynamic constitutive model of concrete basedon damage are built.Using Ansys and programming, obtained by the finite elementmethod of theconcrete specimens of dynamic bending stress strain curve and thetest results are basically consistent, which proves that the proposed constitutive modelwithreference.