ф63.5mm外平钻杆接头抗扭强度数值分析

Numerical Analysis of Torsional Strength for ф63. 5 mm Outer-Flat Drill Pipe's Joints

采用有限单元法对ф63.5mm外平钻杆接头的抗扭强度进行了数值分析,结果表明,该规格的钻杆接头能够承受的最大扭矩约为6 030 Nm,分析结果与试验结果一致。在此扭矩下,钻杆最大等效应力出现在公接头锥扣大端螺纹处,值为960.29 MPa,约等于钻杆材料的屈服强度960MPa。母接头此时的最大等效应力为801.9 MPa,位于母接头锥扣的小端螺纹处。分析结果合理地解释了在钻杆实际使用过程中公接头经常先断裂的原因。

Torsional strength of the Φ63.5 mm outer-flat drill pipe＇ s joints is calculated with the finite element method. The results show that the maximum torque is about 6030 Nm which the specific drill pipe＇ s joints can withstand and the calculation results are consistent with the experimental results. Under this torque, the maximum equivalent stress of the male screw is 960.29 MPa, approximately equal to the yield strength value 960 MPa of the drill pipe＇ s material and the max value is in the big end of the male joint＇ s taper hole. The maximum equivalent stress of the female screw is 801.09 MPa and the max value is in the small end of the female joint＇ s taper hole. From these results, gets a reasonable explanation of the situation that in the process of drill pipe＇ s actual use, the male screw often fractured firstly when the female screw is relatively intact.