Study on the fragmentation of granite due to the impact of single particle and double particles

Particle Impact Drilling (PID) is a novel method to improve the rate of penetration (ROP). In order to further improve the performance of PID, an investigation into the effect of single and double particles: (1) diameter; (2) initial velocity; (3) distance; and (4) angle of incidence was undertaken to investigate their effects on broken volume and penetration depth into hard brittle rock. For this purpose, the laboratory experiment of single particle impact rock was employed. Meanwhile, based on the LS-DYNA, a new finite element (FE) simulation of the PID, including single and double particles impact rock, has been presented. The 3-dimensional (3D), aix-symmetric, dynamic-explicit, Lagrangian model has been considered in this simulation. And the Elastic and Holmquist Johnson Cook (HJC) material behaviors have been used for particles and rocks, respectively. The FE simulation results of single particle impacting rock are good agreement with experimental data. Furthermore, in this article the optimal impact parameters, including diameter, initial velocity, distance and the angle of incidence, are obtained in PID.