Parameter calibration of a discrete element simulation model for dry lightweight heterogeneous media

In order to realize the discrete element simulation of dry light shaped particle medium in the process of rolling grinding, in this paper, walnut shell particle medium was taken as the research object, the multi-dimensional method is used to divide the light medium with different shapes , and different types of shaped particle media were constructed , the discrete element simulation parameters are calibrated by the combination of physical experiment and simulation. First of all, the intrinsic parameters (density, elastic modulus and shear modulus) of walnut shell particle medium were measured by physical tests. The static friction coefficient、rolling friction coefficient and collision recovery coefficient between walnut shell particle medium and acrylic are 0.422、0.175 and 0.246, respectively, and the collision recovery coefficient between walnut shell particle medium is 0.340. Secondly, the range of static friction and rolling friction coefficients between granular media is determined based on EDEM embedded GEMM database, and the two-factor five-level rotational orthogonal combination simulation test was carried out, The second-order regression equation of accumulation Angle and friction coefficient was established, aiming at physical accumulation Angle 44.64°, the regression equation was optimized and solved, and the best combination was obtained: The coefficient of static friction between granular media is 0.829、the rolling friction coefficient is 0.191. Finally, by setting the different lifting speed of the baffle, the verification experiment of stacking Angle is carried out. The results show that the comprehensive relative error is less than 4%.It is shown that the parameter combination can be used as a discrete element simulation model parameter in the process of rolling grinding with walnut shell particle medium.