Affiliations: [a] College of Mechanical Engineering, Dalian University, Dalian, Liaoning, China | [b] College of Mechanical and Electrical Engineering, Lingnan Normal University, Zhanjiang, Guangdong, China
Correspondence:
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Corresponding author: Jianwei Wang, College of Mechanical Engineering, Dalian University, Dalian, Liaoning, China. E-mail: wangjw72@163.com.
Abstract: To reduce the failure probability of gas drainage drilling holes in coal mines, a new modeling method of gas drainage drilling machine is presented. Firstly, each drill pipe is regarded as a flexible body, and the Lagrange’s equation of second kind is used to model it. Secondly, the joint of drill bit, hole wall and drill pipe are regarded as rigid bodies, and the Newton-Euler method is used to model it. Thirdly, the rigid-flexible coupling multi-body dynamic model of drilling rig-drill pipe-hole wall system in medium and short horizontal section of soft coal seam is established by using relative node coordinate method, and the time complexity and operation complexity of modeling are reduced by using ADAMS macro program. Finally, the finite element method is used to discretize the model, and the virtual prototyping technology is used to solve the mathematical model. The simulation results show that the coupling of friction and vibration does not necessarily increase the probability of drilling failure, but sometimes reduces the amplitude of vibration. Compared with the length of each drill pipe, the influence of drilling depth on the system is greater, and the bit-bounce behaviours is more likely to occur in the deep hole. The operating frequency range of the drilling rig is 6.9E-3 to 2.1E+4Hz. When the length of the drill pipe is constant, the natural frequency of the system increases with the increase of the order, while the natural frequency of the deep hole section is almost unaffected by the order. In practical engineering, the vibration excitation of the actuator should be controlled to avoid the natural frequency. Meanwhile, the modal frequency should be avoided as far as possible to reduce the vibration and the failure probability of drilling holes. The model can simulate a series of dynamic responses of drilling rig system in drilling process, and provide theoretical support for subsequent multi-factor coupling modeling.
