A size-dependent viscoelastic normal contact model for particle collision

作者：Ye, Yang; Zeng, Yawu^*

来源：International Journal of Impact Engineering, 2017, 106: 120-132.

DOI：10.1016/j.ijimpeng.2017.03.020

• Viscoelastic normal contact model
• Size-dependence
• Normal restitution coefficient
• Contact time
• Discrete element method

Considering different energy dissipation mechanisms, many normal contact models have been proposed. However, the size effect and velocity effect of normal restitution coefficient (NRC) cannot always be accurately described. In addition, most of the normal contact models have unphysical tension stage for particles without adhesion during the simulation of particle collisions. Such problems limit the application of discrete element method (DEM) in particle dynamics. Given such limitations, the normal contact model proposed in the present work consists of a nonlinear Hertz spring and a size-dependent nonlinear dashpot, and the model parameters are determined by the NRC obtained in lab tests. Compared with other viscoelastic contact models, the current model can effectively alleviate the influence of unphysical tension force stage on the calculated results, satisfying the accuracy requirement of calculation, and accurately describe the size effect and velocity effect of the NRC of marble spheres at the same time. Besides, due to the viscous force, the contact time calculated by the current model is a little larger than the elastic contact time. The relationship between model parameters and particle size has been analyzed, which shows the law of k(1) conforms to exponential decay law and the K-2 conforms to hyperbolic tangent function.

• 出版日期2017-8
• 单位武汉大学