非粘结柔性立管轴对称载荷作用下的理论模型分析

Theoretical model analysis of unbonded flexible riser under axisymmetric load

非粘结柔性立管结构复杂,建立一个高效的力学模型非常关键。本文基于最小势能原理,建立了柔性立管在轴对称荷载作用下的刚度矩阵,通过罚函数方法得到表示层间法向接触关系的附加矩阵,将2个矩阵相加即得到柔性立管的整体刚度矩阵。利用此模型讨论了罚参数的取值,分析了柔性立管在拉伸和扭转荷载作用下的力学响应,并与数值模拟和实验结果进行了对比。研究表明:罚参数的取值越大,计算精度越高,但是取值过大会引起方程病态,结果不准确。该理论模型能够正确反映非粘结柔性立管在轴向拉力和扭矩作用下的力学特性,为工程设计的初始阶段提供了一定的参考依据。

The structure of unbonded flexible riser is complex,so it is very important to build a high-efficiency mechanical model.Based on the principle of minimum potential energy,the stiffness matrix of flexible riser under axisymmetric load is derived in this paper.By adding the additional function of normal contact between layers,the matrix of riser contact of is obtained,and the global stiffness matrix of flexible riser is obtained by adding the two matrices.Based on this model,the penalty parameters are discussed,and the mechanical responses of flexible risers under tensile and torsional loads are analyzed and compared with numerical simulation and experimental results.The results show that the larger the penalty parameter,the higher the calculation accuracy;but if the penalty parameter is too high,the equation will be ill conditioned and the result will be inaccurate;the theoretical model can correctly reflect the mechanical characteristics of the unbonded flexible riser under the axial tension and torque,which provides a certain reference for the initial stage of engineering design.