Smooth and non-smooth approaches to simulation of granular matter

Granular matter is defined as a collection of particle grains, such as sand.This type of matter have different characteristics (solid, liquid and gas) depending on the energy level per grain. There are several approaches to modeling and numerical simulations of granular matter. They are used by different groups for different purposes, and the choice between the approaches is based on knowledge and tradition rather than what might be best for the purpose. The key questions are when to use what method and what physical quality is lost depending on the choice.Two regimes of discrete element granular simulations emerge: smooth and non-smooth. To compare the efficiency and physical quality of the two approaches, four physics softwares are examined including Bullet Physics, LMGC90, AgX and LIGGGHTS. Test scenes are setup in each software and the results are compared to each other or to the results of other work.The thesis is performed at UMIT Research Lab at Umeå University