Abstract
Fatigue fracture is the main failure form of mining drill pipe joints, which directly leads to the occurrence of drill pipe drop accidents. Based on the principle of engineering bionics, the spine structure and kinematic behavior characteristics of cheetah were studied; the bionic design and trial production of drill pipe joints were carried out. For the bionic drill pipe joint, it separates the torsion transmission function from the connection function, and when the torsion transmission function of the joint fails, the connection function is still effective, so as to achieve the effect of “breaking the bones and connecting the ribs.” The mechanical and flow field properties of the bionic drill pipe joint were analyzed. Mechanical test results showed that, for the bionic drill pipe joint, the average tensile capacity was 555.48 kN and the average torsion capacity was 8914.13 N·m, which met the mechanical performance requirements. The flow field numerical simulation results showed that, when the drilling fluid velocity field and pressure field were stable and change evenly, there is no risk of leakage. The study results can provide a new research idea for the research and development of mine drill pipe joint with long life and antidropping function.
Highlights
Drilling technology is widely used in the fields of gas drainage and water hazard control in coal mines, which is of great significance to the safe production of coal mines
During the drilling process in coal mine, the force of the drill pipe joint is complicated, and due to the limitation of the space size of underground roadway, there has more threaded connections for the drill pipes, which leads to the rigidity of the pipe is strong, and the fracture accidents of the drill pipes occur from time to time [1]
The drill pipe is severely bent in the hole, and stress concentration is likely to occur at the root of the external thread, which leads to the fracture of the drill pipe and the formation of the “drop drilling” accident
Summary
Drilling technology is widely used in the fields of gas drainage and water hazard control in coal mines, which is of great significance to the safe production of coal mines. The drill pipe is severely bent in the hole, and stress concentration is likely to occur at the root of the external thread, which leads to the fracture of the drill pipe and the formation of the “drop drilling” accident. (1) New materials: research the materials with better comprehensive performance and improve the overall performance of external threads For example is He who took 4145H material and φ88:9 mm drill pipe joint thread (NC38) as the research object, and he applied the nanocopper antifriction coating AFRICO to the joint thread, so as to achieve the purpose of improving the antisticking performance of the thread [7]. The core of the above measures is to reduce the stress concentration at the root of the external thread, but it does not essentially solve the problem of drill pipe “drop drilling” caused by the fracture of the external thread. By using laser cutting and alloy die-casting methods, the drill pipe joint is processed into a combination of three parts: the torsion shoulder, the cushion layer, and the front thread, which can achieve the effect of “breaking the bones and connecting the ribs.” By means of laboratory test and numerical simulation, the mechanical and flow filed performance of the bionic drill pipe joint is analyzed, and the reliability of the design is explained, so as to explore a new research idea for solving the problem of drill pipe “drop drilling.”
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
