Vibrational energy transfer via modulated impacts for percussive drilling

In this paper, a new method of vibrational energy transfer from high-frequency low-amplitude to low-frequency high-amplitude mechanical vibrations is proposed and investigated, for the purpose of percussive drilling. The mechanism uses an impact loading comprised of two frequencies forming a beat which excites a structure tuned to the beat-frequency. This concept has been modelled and experimentally verified. It is postulated that the efficiency of this technique is strongly dependent on the strength of nonlinearity in the system. The vibrational energy transfer is significantly reduced for superharmonic responses of the system. Practical applications of this mechanism can been seen as new generation percussive drilling tools.