振动工况下特殊螺纹接头密封性能仿真研究

Simulation Study on Sealing Performance of Special Threaded Connector Under Vibration Conditions

因管柱振动导致特殊螺纹接头密封失效的问题,传统的静力学理论无法有效解释。为此,基于能量耗散理论,考虑密封面微观接触滑移的影响,建立了锥面-锥面特殊螺纹接头有限元模型,通过振动模态分析及摩擦接触分析,研究不同模态振型与上扣扭矩下特殊螺纹接头的能量耗散与密封性能。研究结果表明:基于能量耗散理论,利用力-位移迟滞特性分析密封面的接触滑移状态及能量耗散,可从微观层面解释因管柱振动引发特殊螺纹接头密封性能减弱的问题;模态振型下,特殊螺纹接头密封面间的摩擦力与能量耗散均随上扣扭矩的增大而增大,且3阶模态振型的能量耗散值大于1阶模态;特殊螺纹接头密封面的位移为微米级,密封面的摩擦力-位移迟滞曲线呈“针叶”形,处于黏着与滑移共存的微观滑移状态;长期振动工况下,易造成密封面磨损,导致特殊螺纹接头密封性能减弱甚至密封失效。研究成果可为特殊螺纹接头上扣扭矩控制及动载作用下密封性能评估提供参考。

The traditional statics theory cannot effectively explain the sealing failure of special threaded connector caused by pipe string vibration.Therefore,in the paper,based on the theory of energy dissipation,considering the influence of micro contact slip of the sealing surface,a finite element model of cone-cone special threaded connector was built;then,by means of vibration mode analysis and friction contact analysis,the energy dissipation and sealing performance of the special threaded connector under different modal shapes and make-up torques were studied.The study results show that based on energy dissipation theory,the problem of weakened sealing performance of special threaded connector caused by pipe string vibration can be explained from a microscopic level by using the force-displacement lag characteristics to analyze the contact slip state and energy dissipation of the sealing surface;under the modal shape,the friction and energy dissipation between the sealing surfaces of the special threaded connector increase with the increase of the make-up torque,and the energy dissipation value of the third-order modal shape is greater than that of the first-order modal shape;the displacement of the sealing surface of special threaded connector is at micron order,and the friction-displacement lag curve of the sealing surface is“needle-like”,in a micro slip state where adhesion and slip coexist;under long-term vibration conditions,the sealing surface easily wears and tears,leading to weakened sealing performance or even sealing failure of special threaded connector.The study results provide reference for the make-up torque control of special threaded connector and the evaluation of sealing performance under dynamic load.