单钢保温管道S形铺设分析的传递矩阵法

S-lay analysis of cased insulated flowline based on transfer matrix method

单钢保温管道实施S形铺设时,弯曲刚度因混凝土配重层损伤而变化,若要准确分析管道现场接头位置的钢管层应力,就需要考虑管道配重段因弯曲损伤而产生的刚度折减。本文基于混凝土损伤塑性模型,应用有限元法分析弯曲过程中单钢保温管道混凝土配重层的拉伸开裂与压缩破碎,并用与钢管层曲率相关的无因次刚度比表征因配重层损伤导致的管道刚度变化。应用传递矩阵法,结合管道在托管架上的曲率变化,计算铺设管道现场接头位置的附加弯矩,作为现有铺管分析的非线性修正。提出了单钢保温管道S形铺设的上限刚度和下限刚度概念,并与混凝土配重层损伤程度关联,作为该种类型管道铺设刚度控制的基本准则。

During S-lay the bending stiffness of cased insulated flowline changes due to the damage of its concrete weighted coat.If we want to accurately calculate the stress in the carrier pipe at field joints of this kind of pipeline,the bending stiffness reduction of the pipeline should be taken into consideration.Based on concrete damaged plastic model,tension cracking and compression collapse of weighted coat,cased insulated flowline bending are analyzed by the finite element method to build up the nonlinear relationship between bending stiffness and curvature of this kind of pipeline system.And the additional bending moment in pipe field joints are calculated using transfer matrix method as a nonlinear modification of pipe installation analysis.The upper limit and the lower limitare proposed in this paper to provide a bending stiffness control criterion for the S-lay of cased insulated flowline.