Optimal Design Parameters of a Percussive Drilling System for Efficiency Improvement

Table 2

Dynamic drill-bit properties for loading, unloading, and τ, and the damping modes capable of reaching u_m.

Case no.	Conditions	Damping modes capable of reaching um
		1		Over	Over	Over
2		Over	Over	Critical
3		Over	Over	Under
4		Critical	Critical	Under
5		Under	Under	Under
6
		Under	Under	Under

Damping modes capable of reaching u_m.