Authors: L. Xu, M. Anjanappa
Addresses: Black and Decker Corporation, 701 E. Joppa Road, Towson, MD 21286, USA. ' The Department of Mechanical Engineering, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA
Abstract: Percussive drilling, that uses rotary torque and axial impact simultaneously, is an established method of making holes in concrete. This paper deals with the development of a finite element model, based on three-dimensional wave propagation, which represents the impact process of percussive drilling in concrete. The solid model of the percussive drilling system consists of five separate components, viz. shank, fluted body, socket tip, carbide blade and concrete target. After integration and meshing, the finite element model is analysed using three-dimensional wave propagation techniques. The bias weight and the impact impulse were set up as inputs to the drilling system. A ||surface to surface eroding|| interface was selected for the drill tip-concrete contact surface while a ||rigid wall|| interface was chosen for the concrete-ground support contact surface. Simulation results showed the usefulness of the model in understanding how the three-dimensional wave, due to impact, propagates through the drilling system resulting in penetration of the drill bit into concrete. The accuracy of the model was successfully verified with prior-known one-dimensional analytical model and experimental penetration results. Finally, to illustrate the potential use of this model to design and analyse percussive drilling system, the effect of variation of rake angle, helix angle, point angle, and bias weight on the extent of penetration is presented. The results clearly showed the importance of simulating the impact process for designing new percussive drill bits.
Keywords: percussive drilling; concrete; finite element analysis; FEA; wave propagation; impact process; simulation.
International Journal of Computer Applications in Technology, 2005 Vol.24 No.1, pp.1 - 16
Published online: 23 Jun 2005 *Full-text access for editors Full-text access for subscribers Purchase this article Comment on this article