Experimental study on stress distribution of directional drill pipe joint based on electrical measurement method

Abstract:

The directional drill pipe in coal mine is subjected to bending， torsion， vibration， tension and other loads in the hole， and the fracture accident often occurs in the construction process. The main reason for the fracture of drill pipe is stress concentration. Based on the resistance strain measurement， this paper builds a full-size physical stress test platform for directional drill pipe， conducts tensile stress tests on drill pipe joints， and plots each experimental data into stress distribution curves. The results show that the stress of drill pipe pin is greater than that of drill pipe box， and the maximum stress of drill pipe pin and box is at the position of tooth 3. The correctness of the simulation model is verified by the stress distribution trend and the stress value of each tooth， and a method to verify the drill pipe simulation model is provided. The experimental data and stress distribution curve in this study provide reliable data support for the finite element simulation of drill pipe.

Key words:directional drill pipe;connection thread;stress test;resistance strain;stress distribution