Optimized differential evolution algorithm for solving DEM material calibration problem

The discrete element method (DEM) micro parameter calibration has been a longstanding problem since the DEM was created. To date, the low-precision and time-consuming calibration procedures still pose difficulties for DEM applications. This study proposed an optimized differential evolution calibration method (OpDEC) to calibrate cohesive granular DEM material to the target macro mechanical properties. Macro parameter Young’s modulus, Poisson’s ratio, uniaxial compressive strength, and direct tensile strength can be calibrated to less than 5% weighted relative error within 5 h or less than 1% weighted relative error within 12.5 h. For this purpose, 180 calibrations were carried out to optimize the mutation strategy and control parameters of the differential evolution algorithm. A calibration evolutionary health monitoring scheme was devised to detect the possible ill calibrations in early time. The algorithm robustness was verified by 50 calibrations of 5 types of rock. Moreover, a laboratory-tested stress–strain curve of Äspö diorite was compared with 10 calibrated DEM models that showed a good agreement in terms of axial behaviour. The OpDEC has a great potential to serve as a fast and easy-to-implement method to calibrate the cohesive granular DEM material.