Numerical Simulation of Dynamic Mechanical Behavior of Concrete with Two-dimensional Random Distribution of Coarse Aggregate

With concrete regarded as a two-phase non-homogeneous composite material consisting of coarse aggregate and cement mortar and on the basis of Fuller gradation curve and Walaraven plane conversion formula, a two-dimensional circular aggregate random distribution program of the concrete was designed to simulate the dynamic response of the concrete subjected to impact loading.The influences of impact velocity, specimen dimension, size and distribution of coarse aggregate and volume fraction of coarse aggregate on the dynamic mechanical behavior of the concrete were analyzed, and the impact failure mode of the concrete was also discussed.The regulations of impact velocity, specimen dimension, size and distribution of coarse aggregate and volume fraction of coarse aggregate on the dynamic mechanical behaviors of the concrete were presented.Our numerical simulation shows that the peak stress of the concrete increases with the impact velocity, and thus the concrete is rate-dependent.With the enhancement of the specimen dimension, the peak stress of the concrete decreases, so the concrete produces an obvious size effect.With the volume fraction of coarse aggregate, the peak stress of the concrete increases at first and then declines.When the volume fraction of coarse aggregate equal to 40%, the peak stress of the concrete reaches its maximum value.With the increase of the minimum diameter of coarse aggregate, the peak stress of the concrete declines.However, with the increase of the maximum diameter of coarse aggregate, the peak stress of the concrete increases initially and then declines, which provides a theoretical guidance and technical support for the engineering application of the concrete.