Mechanical Analysis and Structural Optimization of Air Hammer Drill Teeth Based on ANSYS /LS_DYNA

Abstract

Air drilling is a prevailing technology of oil and gas energy industry in today’s world, it can solve problems when drilling in complex layer that can not be done by conventional drilling way. At the same time, some failures of dill bit teeth in air hammer drilling like teeth falling, breaking and severe abrasion seriously affect the drilling efficiency. Thus this paper intended to investigate rock breaking criteria and damage constitutive model, establish a finite element simulation model of single tooth rock breaking and use the impact of dynamic finite element software ANSYS/LS-DYNA to analysis characteristics of rock crushing under confining pressure, which includes fragmentation process, drilling tooth impact and the crush volume of rock broken. The study found that the tapered tooth has the highest efficiency in rock breaking under the same conditions and with edge teeth at 25°angle that increases the rock crushing volume significantly. In addition, the configuration of tooth surface was examined, which showed that the pattern of “spherical teeth in the middle and tapered teeth in the peripheral” has highest rock breaking efficiency.