Summary
This report describes a twodimensional computer model that is suitable for studying flows of dry particles in which the particles are allowed to break. The model is based on discrete particle computer simulations. Here, macroscopic polygonal particles are constructed by ugluingn together small elements (hereafter referred to as “elementsn). Depending on the stress conditions the glued bonds can respond elastically, undergo plastic failure or break, allowing cracks to propagate across the macroscopic particle along the boundaries between their microscopic constituents.
In essence, this process creates a simulated material. The manner in which the microscopic elements are organized has an effect on the mechanical behavior in much the same way that the organization of molecules affects the behavior of a real solid. For example, the material must have internal, crystal-like slip planes in order for the resultant material to exhibit plastic behavior. Similarly, the elastic behavior of the bulk material depends on both on the the microscopic element shape and on the spring constants used to model the interactions of the microscopic elements. Consequently, many element shapes and arrangements of elements have been investigated.
Some examples are presented, including compression failure of a rectangular sample, the impact of particles with a plate or binary impacts of particles. Some preliminary simulations of the Utah ball-drop experiments have also been performed that show good qualitative agreement.