非线性对石油井架承载力的影响

Effect of Nonlinearities on Capacity of Derricks

对JJ300/43-A型井架进行了非线性有限元分析,采用空间梁单元,通过包含单元几何刚度阵和变形刚度阵的增量切线刚度法考虑大变形问题,采用弧长法迭代计算,最终得到考虑几何和材料双重非线性情况下井架钢结构的极限承载力。计算结果表明,采用几何和材料双重非线性的分析方法能准确评估井架的极限承载力。为深入研究井架结构的安全度和可靠性评定提供了分析基础。

A method for double nonlinear analysis of the loading capacity of JJ300/43-A derricks is presented in this paper. A spatial beam element is adopted in the nonlinear analysis. The large deformation of the structure is considered by constructing the incremental tangent stiffness matrix which consists of both geometric stiffness matrix and deformation matrix. The ultimate load of the structure is tracked using the arc-length method. Results show that in order to determine the ultimate load capacity of the derricks, both geometrical and material nonlinearities must be considered. A basis of structural analysis is provided for further studies on safety and reliability assessment of the structure of derrick under working conditions.