Studies on the formation of discontinuous rock fragments during cutting operation

A rock fragmentation process is simulated during mechanical cutting of rock using an explicit finite element code, LS-DYNA. In the simulation, a cutting tool is orthogonally moved against stationary rock materials made of sandstone and limestone. Rock material properties have been incorporated using an advanced damage constitute material model. Simulations were performed for various rake angles at different cutting velocities and cutting depths. The variation of cutting forces, stresses, rock fragment morphology and the character of fragment formation have been investigated. Overall, the results indicate that the explicit FEM is a powerful tool for simulating rock cutting and the fragmentation process. More specifically, the separation of rock fragments from the base rock slab was accurately predicted using the numerical model. The cutting forces and rock fragment characteristics were strongly influenced by rake angle when compared to cutting tool velocities for a given depth of cut. This information is shown to be highly pertinent to better understanding cutting rates and tool wear.