Rolling and sliding in 3-D discrete element models

• Published in: Particuology Vol. 23; no. 6; pp. 49 - 55
• Main Authors: Wang, Yucang, Alonso-Marroquin, Fernando, Guo, William W.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.12.2015
• Subjects: Discrete element method; Rolling; Sliding; 三维; 元模型; 变形过程; 滚动阻力; 相对运动; 离散单元法; 纯滑动; 颗粒材料; Rolling; Sliding; Discrete element method
• ISSN: 1674-2001; 2210-4291
• DOI: 10.1016/j.partic.2015.01.006

Rolling and sliding play fundamental roles in the deformation of granular materials. In simulations of granular flow using the discrete element method （DEM）, the effect of rolling resistance at contacts should be taken into account. However, even for the simplest case involving spherical particles, there is no agreement on what is the best way to define rolling and sliding; various versions of definitions and calculations of rolling and sliding were proposed. Some even suggest that a unique definition for rolling and sliding is not possible. We re-check previous studies on rolling and sliding in DEMs and find that some researchers made a conceptual mistake when dealing with pure sliding between particles of different sizes. After considering the particle radius in the derivation of rolling velocity, the results yield a unique solution. Starting with clear and unique definitions of pure rolling and sliding, we present the detailed derivation and validate our results by checking two special cases of rolling. The decomposition of the relative motion is objective; that is, independent of the reference frame in which the relative motion is measured.