Calibration of wet sand and gravel particles based on JKR contact model

The parameters of wet sand and gravel particles with different shapes are calibrated based on JKR contact model. The results reveal that surface energy and rolling friction coefficient are the significant factors affecting the tangent of repose angle, indicating the great influence on the simulation accuracy of wet sand and gravel particles during vibration screening. In addition, the tangent of repose angle and error between simulation and experiment both increase with the filling ball radius increasing, and the corresponding simulation accuracy decreases. Then the screening efficiency is further investigated to verify the accuracy of the calibration parameters. The parameters calibrated can well simulate the screening process. And it is found that non-spherical model instead of spherical model can better simulate the screening process of sand and gravel particles. Meanwhile, JKR model is also verified to better simulate the screening process than Hertz-Mindlin model. Moreover, as the filling ball radius increases, the screening efficiency increases while the simulation time and file size are greatly reduced. However, the corresponding error between simulation and experiment increases. Considering the error and screening time, the optimum filling ball radii for flat, triangular cone and ellipsoid particles are 2 mm, 1.5 mm and 1 mm, respectively.