一种钻柱动态疲劳断裂性能测试装置的研制及其测试结果分析

Development of A Test Device for Dynamic Fatigue Fracture Behavior of Drill String and Analysis of Its Test Results

针对钻进过程中钻柱承受交变应力、振动冲击载荷的恶劣工况,研制出模拟钻柱多冲疲劳断裂的测试评价装置,对广泛应用的S135钻杆材料进行了系统的测试研究。结果表明:与单次冲击的夏比冲击功指标相比,多冲动态断裂累积能量指标测试数据波动小、可靠性更好;钻杆加厚过渡带相比管体刺穿、断裂严重,其重要原因之一是该部位材料材质分布不均匀、各向异性严重;随单次冲击功增大,钻杆材料的多冲动态断裂次数呈指数式递减,类似疲劳失效的S-N曲线。

Aiming at the bad working conditions of drill string under alternating stress and vibration impact load during drilling, a simulation device for multi-impact fatigue fracture test and evaluation of drill string was developed, and the widely used S135 drill pipe material was tested using it. The results show that compared with the Charpy impact work index of single impact, the cumulative energy index of multi-impact dynamic fracture has less fluctuation and higher reliability;Compared with the pipe body, the thickening transition zone of drill pipe is more serious in penetration and fracture, which is because the material is inhomogeneous and anisotropic in this part;With the increase of single impact energy, the multi-impact dynamic fracture number of drill string material decreases exponentially,which is similar to the S-N curve of fatigue failure.