Based on the conclusions of statical analysis, the discussion on the stability of helical equilibrium of the rod under axial compression was continued in the category of dynamics.
基于静力学分析的结论，在动力学范畴内继续讨论轴向受压螺旋杆平衡状态的稳定性。
2
The calculating formula for critical axial load of worn rod string and tubing was set up.
建立了铅垂油井杆管偏磨临界轴向压力的计算公式。
3
A method for calculating the axial feed of expanding rod is also advanced through the analysis of expander's motion.