煤矿钻杆在严苛的服役环境和复杂的受力状态下易失效,不仅影响正常生产,而且还因打捞困难致使事故恶化.针对上述问题,以煤矿∅73 mm外平定向钻杆为研究对象,对不同载荷下钻杆接头进行了受力分析,并通过单轴拉伸试验获得了接头材料的力学性能参数,构建了接头材料的本构模型.在此基础上,应用虚功原理、Von Mises 屈服准则和接触非线性理论建立了钻杆接头螺纹的弹塑性有限元分析模型,分析了不同工况载荷作用下接头部位的受力状态及应力场分布规律.研究结果表明:在预紧扭矩为 2000 N·m时,该钻杆接头具有良好的密封性能和联接强度;单扭和拉扭载荷下,靠近主台肩的第一螺纹牙为主要失效部位;在压、弯、扭载荷下,主台肩为主要失效部位;在钻机最大扭矩与推进力的作用下,接头的抗弯能力达到3°/3 m.
Three-dimensional mechanical characteristics of mining directional drill pipe joints under composite loading
Due to the harsh service environment and complex stress state,mining drill pipe is prone to failure,which seriously affects normal production and worsens the accident due to salvage difficulties.The forces on the Φ73 mm outer-flat directional drill pipe joints were analyzed under different loads.The mechanical property parameters of the joint material were obtained through uniaxial tensile tests,and the constitutive model of the joint material was constructed.Then,the elastic-plastic finite element analysis model of the drill pipe joint thread was established,applying the virtual work principle,Von Mises yield criterion,and contact nonlinear theory to analyze the stress state and stress field distribution of the joint under the action of loads in different working conditions.It was demonstrated that the drill pipe joint exhibits satisfactory sealing performance and connection strength at a preload torque of 2000 N·m.The first thread tooth near the main shoulder is the primary failure site under both single torsion and tension torsion loads.Meanwhile,the main shoulder is the principal failure location under compression,bending,and torsion loads.Moreover,under the combined effect of the maximum torque and thrust of the drilling rig,the joint's bending resistance is up to reach 3°/3 m.
drill pipe jointborehole curvaturecombined loadthree-dimensional finite element analysis
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万方数据
