摘要
由于API螺纹抗弯扭性能较差,导致接头螺纹的使用寿命会低于其设计寿命。以API NC50钻杆接头螺纹为例,通过改变API螺纹台阶面结构来增强API螺纹的抗扭性能。首先,通过万能材料试验机得到了35CrMo的材料性能参数,建立螺纹材料的本构模型;其次,基于材料本构模型建立了钻杆接头螺纹有限元分析模型,并验证了该分析模型的准确性;最后,分析了钻杆接头螺纹在上扣载荷、上扣+压缩载荷和上扣+压缩+弯曲载荷下的螺纹牙应力场情况。分析结果表明:梯形台阶面结构能够有效改善接头螺纹扭矩的分布,使螺纹牙所承受的扭矩值降低了50%;在上扣+压缩载荷工况下,螺纹牙上最大应力总体变化趋势为随着压缩载荷增加而不断降低,且梯形台阶面螺纹牙上的最大应力低于API螺纹结构;当增加弯曲载荷后,钻杆外螺纹螺纹牙应力均随着井眼曲率的增加而增加,但未超过材料的最大屈服极限,梯形台阶面螺纹牙应力也低于API螺纹。
Due to the poor torsion resistance of API thread,the service life of joint thread will be lower than its design life.In this paper,taking API NC50 drill pipe joint thread as an example,the anti-torsion performance of API thread was enhanced by changing the structure of API thread step surface.Firstly,the material performance parameters of 35 CrMo were obtained by universal material testing machine,and the constitutive model of thread material was established.Then,based on the material constitutive model,the finite element analysis model of drill pipe joint thread was established,and the accuracy of the analysis model was verified.Finally,the stress field of drill pipe joint thread under make-up load,make-up+compression load and make-up+compression+bending load were analyzed.The results show that the trapezoidal step surface structure can effectively improve the torque distribution of the joint thread and reduce the torque value of the thread by 50%;under the condition of make-up + compression load,the overall variation trend of the maximum stress on the thread continuously decreases with the increase of the compression load,and the maximum stress on the thread tooth of the trapezoidal step surface is lower than that of the API thread structure;when the bending load is increased,the maximum stress on the thread tooth of the trapezoidal step surface is lower than that of the API thread structure After that,the thread tooth stress of drill pipe female joint increases with the increase of dogleg degree,but it does not exceed the maximum yield limit of the material,and the thread tooth stress of trapezoidal step surface is also lower than that of API thread.
作者
陈波
林春花
CHEN Bo;LIN Chunhua(School of Mechanical Engineering,Southwest Petroleum University,610500 Chengdu,China)
出处
《应用力学学报》
CAS
CSCD
北大核心
2022年第1期155-162,共8页
Chinese Journal of Applied Mechanics
基金
国家自然科学基金资助项目(No.51905458)。
关键词
钻杆螺纹
梯形台阶面
上扣扭矩
井眼曲率
有限元分析
drill pipe thread
trapezoidal step surface
make-up torque
dogleg degree
finite element analysis
