Bending and twisting friction models in soft-sphere discrete element simulations for static and dynamic problems

In soft-sphere discrete element models of granular flow, particles may interact in a variety of ways including interactions normal to points of contact and interactions tangential to points of contact such as sliding, rolling, bending and twisting. In the majority of models normal and sliding modes are used. Rolling friction is sometimes reported but incorporation of bending and twisting effects is less common. In this paper it is shown that the precise mathematical nature of bending and twisting models in soft-sphere simulations can have significant effects on model predictions, especially for the case of dynamic granular flow problems. (C) 2015 Elsevier Inc. All rights reserved.