Contact enforcement methods comparison in DEM context: application for railway ballast shear test

Resumo

In the Discrete Element Method (DEM) analysis one has to represent the mechanical contact between particles, which is a need in a model representation in a certain geometric scale. This can be done by numerous methods and assuming distinct interface laws. In this work, two distinct contact enforcement methods are compared: the classical penalty-based and the barrier method. The former is available in Rocky DEM commercial software and the latter is implemented in the academic code GIRAFFE. Both methods are compared with respect to their capabilities, advantages and limitations. A classical shear box test is used as a comparison basis. The granular material tested is a sample of railway ballast. Discussions on aspects of convexity or concavity of particles are also made, such as their influences in overall mechanical results.