Calibration of discrete element parameters for multi - particle bonding model of bulk coal

In this paper, based on the uniaxial compression test of coal samples, the bonding-particle model (BPM) of coal samples was established based on the discrete element method (DEM). The bond parameters of the virtual model are calibrated by combining theoretical calculation, physical test and virtual simulation. The Plackett-Burman test, the climbing test and the response surface test were designed with the critical load Fd and the critical time td of the crushing of the uniaxial compression specimen as the response values, the optimal bond parameters were obtained, namely, the ultimate normal strength coefficient sigma was 1.55 x 107 Pa, the ultimate tangential strength coefficient tau was 1 x 107 Pa, and the tangential stiffness coefficient S tau 2 of the M bond was 9.646 x 1010 N m-3. The multi-particle BPM of bulk coal was established by using this bonding parameter and verified by experiments. The error of simulation test and physical test is less than 13%. The BPM can well characterize the characteristics of bulk coal, which lays the foundation for studying the rigid-scattering coupling effect between bulk coal and equipment, and provides reference for the establishment of multi-particle BPM based on DEM.