Numerical and Experimental Study on Strain Rate Effect of Ordinary Concrete under Low Strain Rate

The strain rate effect of ordinary concrete is researched through the particle discrete element method. A random construction method of three-dimensional aggregate is used, and the numerical sample consistent with the experimental specimen is constructed using particle flow code. Moreover, the simulation method that can properly reflect the strain rate effect with the parallel bond model is proposed. The meso-parameters are calibrated by triaxial compression test. Based on the proposed simulation method and calibrated meso-parameters, the numerical tests of direct tension, uniaxial compression, and cyclic loading under strain rates from 10(-5) s(-1) to 10(-1) s(-1) are carried out. The results show that the strain rate effect of concrete can be simulated with particle flow code by assuming that the micromechanical properties of materials vary with the strain rate, and the strength and failure characteristics of numerical samples under different strain rates are described well by the proposed method. In addition, the different mechanical responses of the samples to the strain rate in the compression test and the tensile test are obtained, and the changes of mechanical parameters and damage degree with strain rates in the cyclic loading test are also successfully simulated. This study can provide a feasible numerical method for the follow-up research of dynamic mechanical behavior of concrete and offer theoretical guidance for the stability assessment of concrete engineering.