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Advances in Materials Science and Engineering
Volume 2018, Article ID 2346598, 13 pages
Research Article

Optimal Design Parameters of a Percussive Drilling System for Efficiency Improvement

1Korea Institute of Industrial Technology, Gyeongsan-si, Republic of Korea
2Department of Mechanical Engineering, Hanyang University, Ansan-si, Republic of Korea
3R&D Center, Soosan Heavy Industries Co., Ltd., Hwaseong-si, Republic of Korea

Correspondence should be addressed to Yun-Joo Nam;

Received 16 June 2017; Revised 9 August 2017; Accepted 10 October 2017; Published 5 February 2018

Academic Editor: Fernando Lusquiños

Copyright © 2018 Changheon Song et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


This paper aims to determine the optimal design parameters for percussive drilling systems considering the bit-rock interaction. First, the motion dynamics of a bit impacted by a dropped piston are modeled by impact stress propagation and a rock-breaking mechanism representing the penetration resistance coefficient and unloading constant. Next, the damping vibration behavior of the bit is investigated considering the impact duration and the rock loading/unloading condition. In addition, the proposed dynamics are simplified by adopting two dimensionless parameters representing the bit-piston mass ratio and the rock-piston stiffness ratio. Finally, the drilling efficiency, defined by the energy transmitted from the piston to the rock, is presented in terms of the proposed parameters. The use of optimal design parameters for percussive drilling systems improved the drilling efficiency. These results are applicable to the design and performance estimation of down-the-hole and top-hammer systems.