Numerical and experimental verification of a damping model used in DEM

This paper presents a study on the damping ratio (beta) used in discrete element simulations. Physical experiments are performed by dropping particles from a predetermined height. Two kinds of granular particles, aluminum and steel spheres, are used. The size of these particles are the same. The process of particle depositing under gravity is simulated using the discrete element method. The experimental observation is compared with the numerical result to identify the appropriate beta. The result indicates that the appropriate damping ratio used in discrete element simulations is between 0.2 and 0.3%. Various beta are then used in the numerical simulations to study the effect of beta on the dropping process. The final height of the sample relates to beta and the drop height. The effect of beta is more profound for small drop height. For greater drop height, the effect of beta is negligible.