Modelling continuous materials using discrete element modelling: investigations on the effect of particle packing

摘要

Preparing the particle packing model is a crucial step in modelling continuous materials using discrete element modelling (DEM) due to the close correlation between particle packing and material property. In this paper, two modified cubic packing models are generated by inserting smaller particles into the void space of simple cubic packing (SCP). Packing fractions and coordination numbers of two modified packing models increase gradually with the increase of insertion times. Size effect of each packing model is investigated and different packing models share the same characteristics, i.e. stress-strain curves of continuous materials created using different packing models under tensile loads tend to concentrate gradually with the increase of size ratio and their peak strengths raises gradually and then converge into constants. Uniaxial tensile DEM simulations are performed to investigate the impact of packing type and packing with or without rectangular defects on the mechanical behavior of continuous materials generated using different packing models. It is proven that SCP has the minimum uniaxial tensile strength compared to binary cubic packing (BCP) and triple cubic packing (TCP). Any packing with one of three kinds of rectangular defects tends to weaken its uniaxial tensile strength. From BCP to TCP, peak strength or stress has only slight improvements while total numbers of sub-particles soar greatly. The newly developed packing models in this paper enhance the understanding of the relationship between particle packing and material property although these models are formulated and computed in 2D.