Finite element method of resistance to pull-off for deep hole wire-line drill rod

Aiming at the problems such as pall-off of joint thread and breaking of rod, based on non-linear finite element method, the analysis and calculation of resistance to pull-off for deep hole wire-line drill rod with several types of thread under different working conditions was carried out by using finite element software. Results showed that barb trapezoidal thread performed best and buttress thread was better under the same thread taper; with smaller thread taper, the pull-off force showed upward trend after the fist under the same type of thread; with larger negative angle, its resistance to thread pull-off was increased; compared with tension, pull-off force decreased slightly under the tension and torsion.