摘要:
通体花键式贯通式潜孔锤反循环钻头在实际施工中尾部较易损坏,影响反循环钻头的使用寿命。为提高反循环钻头的使用寿命,对反循环钻头尾部结构进行了优化设计,并采用非线性动力学仿真软件LS-DYNA对改进前后的反循环钻头进行了仿真分析。分析结果表明:由于在冲锤的高频冲击作用下,反循环钻头尾部易出现较大的局部应力集中,导致钻头体出现疲劳破坏;通过对钻头尾部结构设计优化后,与通体花键式反循环钻头相比,新结构钻头在无泄风槽情况下,应力集中值减小44%,在有泄风槽的情况下,应力集中值减小19%。数值模拟分析表明,优化后能大幅度提高钻头寿命。
Abstract:
The reverse circulation bit tail of spline DTH hammer is easily broken when drilling into extremely complex stra-ta, such as hard, brittle and fragile ones.The structure design of reverse circulation bit tail was optimized to prolong the service life, and the simulation analysis was conducted on the reverse circulation bits before and after improvement by non-linear dynamics simulation software LS-DYNA.It shows that due to the high-frequent impact force of hammer, the reverse drill bit tail is prone to having a big local stress concentration which causes fatigue rupture to the bit body.With the optimi-zation of bit tail structure design, comparing with spline reverse circulation bits, the stress concentration of this new-struc-ture bit decreases by 44%and 19%respectively under the conditions of without or with vent duct.Numerical simulations show that the bit service life can be greatly increased by optimization.
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