In recent years, numerical simulations have been used widely for investigation of mechanical rock cutting. However, the capability of the modelling methods has yet remained open for question. In an attempt to address the shortcomings of the existing methods, this paper proposes a new extension of combined finite/discrete element method (FEM/DEM), which takes into account the mix-mode I-II fracture criteria for predicting the initiation and propagation of cracks. The code's ability in modelling rock fracture process is investigated by simulating fragmentation with a mechanical cutter. The model characterized the rock-tool interaction, computing the direction of crack growth leading to chip generation. The obtained results demonstrated the capability of the proposed combined FEM/DEM method in modelling mechanical rock cutting process. The code could successfully handle the chipping process, being able to model the stress concentration, crack initiation, crack propagation and chip separation.
During the past decades the application of mechanical tools for rock fragmentation has been extended widely in mining and civil engineering industries; providing a more flexible and environmentally friendly alternative to conventional blasting method. However, the rock fragmentation mechanism with a mechanical cutter has not well understood due to the complexity of the dynamic interaction between mechanical tool and rock, and rock fracture process (Ghamgosar and Erarslan, 2015). While rock cutting experiments are largely used to investigate the cutting process and the associated cutting forces, the extensive number of variables and effective factors influencing the process have made the application of these tests relatively limited. The developed analytical and empirical methods also suffer from same drawback. The recent advancements in numerical modelling methods have confirmed to provide robust tools for simulation of complex problems. Hence, different numerical techniques have been considered for investigation of rock fracture process. The rock cutting process comprises of four stages that should be addressed in a numerical simulation;
generation of crushed zone under the tool,
cracks initiation and propagation from crushed zone,
cracks coalescence and chipping process
chip separation. Not all of the numerical techniques are able to model the entire rock cutting process.
