DEM investigation of the effect of arrangement of grains on the behavior of brittle granular materials subjected to one dimensional compression

Granular materials are used in many projects such as dams, railways and breakwaters. Because the size of granular materials in these projects starts from a few centimeters and sometimes reaches to one meter, conducting laboratory experiments would be very expensive, time consuming and even impossible. For this purpose, the use of numerical modeling to investigate the effect of different parameters on the mechanical behavior of this type of material is very important. Among the effective factors, grain arrangement is investigated in this study. Thus, cylindrical and cubic grains are modeled as representative of rounded and angular grains, in two regular and irregular arrangement based on the discrete element method and stress-strain behavior, applied energy and breakage values after loading are investigated. Using the non-linear Hertz model and determining its parameters based on laboratory experiments, controlling the uniformity of grain distribution based on the number of contact points along with the dip and direction of grains, defining the breakage criterion based on Von Mises criterion and applying the breakage pattern based on particle splitting are among the features of the model used. In order to validate the numerical model, similar laboratory experiments were performed and their results were compared with each other. The results showed that the numerical model can study the effect of the arrangement of grains on the behavior of materials with high accuracy. Also, due to the existence of different shapes in granular materials, the effect of mixed arrangement was investigated on the results.