FGQ-600型潜孔锤钻头冲击应力作用下强度可靠性分析

Strength analysis of FGQ-600 type DTH hammer drill bit used for casing while drilling

摘要:

潜孔锤反循环跟管钻头是破碎岩石的主要工具，同时是实现反循环钻进的重要部件之一，广泛应用于地质灾害防治工程中。钻头在钻进过程中承受交变的冲击载荷，易产生应力集中和疲劳破坏。活塞碰撞钻头后产生的应力波传播至钻头与岩石接触面后发生反射引起应力波叠加，使得钻头受力增加。为保证跟管钻头的正常工作，本文利用ABAQUS对不同冲击载荷下FGQ-600型大直径潜孔锤跟管钻头进行模拟及强度分析。结果表明：（1）钻头应力随冲击功增大而增加；（2）在潜孔锤2500 J的冲击功下，钻头体最大等效应力为808.9 MPa，小于材料屈服强度，满足强度要求；（3）起下钻时销轴应力随直径增大而减小，40 mm时销轴最大应力为383.66 MPa，低于材料屈服强度785 MPa，满足强度要求；（4）当销轴直径为16 mm时，销轴发生塑性变形，建议销轴直径≮20 mm。

Abstract:

The DTH hammer drill bit used for casing while drilling is the main tool of rock breaking and it is one of the important components of air reverse circulation drilling tools. It is widely used in geological hazard control projects. During the drilling process， the drill bit is subjected to alternating impact load， which is prone to stress concentration and fatigue failure. The stress waves generated by the piston collision with the bit propagate to the contact surface of the bit and rock， and cause the superposition of stress waves， which increases the stress on the bit. In order to ensure the normal operation of the drill bit， the strength analysis of FGQ-600 large-diameter DTH hammer drill bit under impact load is carried out by the Finite Element Software. The results show that the von-mise stress increases with impact energy. The maximum equivalent stress on the bit is 808.9MPa at the impact energy of 2500J of the DTH hammer， which is less than the material yield strength and meets the strength requirements. When tripping， the stress on the pin decreases with the increase of its diameter. The maximum stress on the 40mm pin is 383.66MPa， which is less than the material yield strength of 785MPa and meets the strength requirements.The pin appears plastic deformation at the diameter of 16mm； thus， it is recommended that the diameter of the suspension pin should not be less than 20mm.