Study on the Damage Effects of Explosive Media Based on FEM-DEM Local Adaptive Transformation

The paper introduces a novel FEM-DEM local transformation method for accurately simulating crack distribution in damaged rock masses. This method converts crushed and cracked rock mass elements into particle elements, avoiding mesh-dependence in crack extension and improving accuracy without compromising computational efficiency. To validate the feasibility of this method, three methods were used for two-dimensional blasting numerical simulations of organic glass (PMMA): the discrete element method (DEM), the continuum-discontinuum element method (CDEM), and the FEM-DEM local transformation method, and the results were compared with experimental data. The results show that the FEM-DEM local transformation method can accurately characterize the crush zone and crack zone of PMMA plates, and is consistent with the experimental results; while DEM and CDEM can only represent the characteristic morphology of PMMA plate crack zone, they are not accurate enough in depicting the crush zone. A three-dimensional blasting funnel model was established using the FEM-DEM method to determine the relative power of three explosives. Combined numerical simulation and experimental analyses were conducted. Results demonstrate that the FEM-DEM method accurately depicts the shape of the blasting funnel with a small error compared to experimental values, confirming its accuracy. Furthermore, the research shows that the porous ammonium nitrate fuel oil explosive has higher brisance than the modified ammonium nitrate fuel oil explosive, while the emulsified ammonium nitrate fuel oil explosive has lower brisance, consistent with numerical calculations and on-site experiments. The findings provide a reliable numerical method for optimizing blasting parameters and advancing precise blasting technology.