Mechanical Simulation of Granular Materials by DEM Analysis

A study of four constitutive contact models employed in discrete element analysis is presented. Most discrete element simulations employ simple contact models due to computational time constraints. However, few works are available in literature which evaluates the suitability of these simple models to simulate DEM applications. The influence of more complex models on bulk behavior is examined through performing a simulated quasi-static biaxial compression test and mapping out simple stress-strain relationships. Furthermore, the effects on behavior of the system while varying porosity (dense or loose) and surface friction coefficient are also investigated. Detail is given in describing the various methods used in the preprocessing stage of the granular assembly. The four contact models in consideration are: linear elastic model, non-linear Hertz-Mindlin model, rigid plastic model, and elastic-plastic model. Also presented, is an investigation into the macroscopic and microscopic mechanical behavior of a stressed assembly employing the linear elastic model. This includes stress-strain behavior and evolution of coordination number.