Experimental Research For Constitutive Relationship In Uni-axial Tensile Of Concrete Under High Strain Rate

In real conditions, concrete structures are inevitably subjected to the dynamic loads, the study of which, in consequence, has profound practical meaning. However, due to many uncertainties, objective or subjective, for example, the distinct difference between dynamic and static behavior of concrete, the stiffness and accuracy of test equipments and the application of different experimental methods, the results of previous experiments vary from each other, and some of them are far from satisfactory. This is where the research starts from.The electro-hydraulic servo loading system was determined to be used in the tension test of concrete. The shape of concrete specimen is rectangular solid. The dimension of specimen is 100mm×100mm×300mm. The amount is 64. While applying the direct felt in this test, the measuring range of the vertical strain gauges must include the entire bound, and the data will be more accurate if the vertical strain gauges are in the flank of moulding surface of the specimen. Through formula deduction, the stiffness of components that connect to the specimens is found to have considerable influence on that of the whole equipment. Adding subsidiary steel structures can enhance the stiffness of the whole. Based on this, the stress-strain curve can be tested.The experiment results show that with the increase of stress rate, the tension strength,critical strain and elastic modulus increase while there are not sensible changes in the Poisson ratio . The shape of the stress-strain curve matches the changes of strain rate, and the curve fit equation is also constructed in accordance.