Calibration of discrete element microparameters of coal based on the response surface method

Abstract

Materials properties can be obtained using the discrete element method through appropriate parameter settings. The accuracy of setting parameters affects the reliability of simulation results. To accurately simulate the mechanical properties of coal, the discrete element models of coal were established. The effects of the parameters of the bonded-particle model on the macroperformance of coal were studied based on the response surface method. The simulation results showed that when the normal contact stiffness per unit area, the shear contact stiffness per unit area, critical normal stress, and critical shear stress are 3.066 × 1012 N/m3, 5 × 1011 N/m3, 2.747 × 107 Pa, and 1.424 × 107 Pa, respectively, the bonded parameters reliably simulated the crushing characteristics of long-flame coal. The increase in stiffness causes the model to fracture earlier but has less impact on the peak value; the strength has a greater impact on the mechanical properties of the model. In this study, the reliability of the comparison between the simulation and test was improved, and a basis was provided for the discrete element parameter calibration of the coal and the setting of simulation parameters for shearer cutting.