煤矿定向钻杆接头螺纹应力集中性研究

Study on Stress Concentration of Directional Drill Pipe Joint Thread in Coal Mine

煤矿定向钻杆使用载荷在远低于钻杆屈服强度的情况下依然经常发生钻杆断裂事故,经过事后分析发现煤矿定向钻杆螺纹应力集中是主要原因,这不仅影响正常生产而且还难以打捞,造成人力、财力的损失。采用非线性接触单元对螺纹配合面之间的接触建立有限元模型,不同类型的加载由拉压、纯预紧力和它们的组合组成应用于模型,通过分析得出了公接头和母接头的最大应力集中系数。

Drill pipe fracture accidents often occur even when the working load of directional drill pipe in coal mine is much lower than the yield strength.After the post analysis,it is found that the stress concentration of the thread teeth of directional drill pipe in coal mine is the main reason,which not only affects normal production but also is diffcult to salvage,resulting in human and financial losses.The nonlinear contact element was adopted to establish a finite element model for the contact between the thread mating surfaces.Different types of loading including tension and compression,pure preload and their combination were applied to the model,and the maximum stress concentration coefficient of the male joint and the female joint was obtained by analysis.