Comparative evaluation of normal viscoelastic contact force models in low velocity impact situations
The issue of the dissipative normal nonlinear Hertz type contact, extensively explored in the discrete element simulations, is addressed. As several viscoelastic normal contact force models equally coexist, selected viscous damping models for spherical contacts (Lee and Hermann, 1999; Tsuji et al., 1992; Kuwabara and Kono, 1987; Hu et al., 2011) are investigated, and a comparative evaluation of these models in single particle and granular chain impact situations is presented. It is shown that these models can be characterised by different values of the inter-particle displacement (overlap) exponent equal to 0, 0.25, 0.5 and 1.5, respectively.
A benchmarking is performed in terms of non-dimensional variables, where a variation of the damping ratio and the contact force for a wide range of coefficient of restitutions is studied. The main purpose of this study is to demonstrate the contribution of models to the propagation of force in a chain of contacting particles. Numerical results and their validation against an available experiments are given. The sensitivity of models to the impact velocity is also illustrated. Finally, based on the investigation’s results, conclusions and recommendations for DEM simulations are given.
Keywords: spherical particle, viscoelastic damping, normal contact, coefficient of restitution.