EMULATION STUDY ON ROCK-BREAKING MECHANISM OF PERCUSSION-ROTARY BIT

The process of establishing the finite element model of the bit-rock interaction in the percussion-rotary drill is introduced.What's more,the process of the rock-breaking by the percussion-rotary bit under rotating impact and simple impact load is emulated with computer,then the process is described herein.The related depth-time and volume-time contrasting curves when the bits break rocks are obtained,and the rock-breaking mechanism of the percussion-rotary bit is concluded.The process of the rock-breaking under rotating impact can be divided into four phases,the depth of the rock-breaking is mainly decided by impact effect but not the effect of rotary,rock-breaking volume under rotating impact is about twice as large as that under simple impact load.Therefore,the theoretic foundations for the further use of percussion-rotary bit in the oil industry are provided.