导管架管节点穿透裂纹应力强度因子数值分析

Numerical Analysis of Stress Intensity Factor of Through-Thickness Crack for Tubular T-Joints in Jackets

采用有限元软件ANSYS建立多个不同尺寸的撑杆焊趾处带穿透裂纹的导管架平台T型管节点有限元模型,载荷分别为施加在撑杆上的轴力和平面内弯矩,采用位移外推法计算裂纹前缘的应力强度因子。首先验证ANSYS计算的管节点撑杆焊趾处穿透裂纹应力强度因子结果随裂纹前缘网格尺寸变化的收敛性,然后初步讨论管节点撑杆壁厚和穿透裂纹角度半宽值对撑杆焊趾处穿透裂纹应力强度因子的影响,得出了应力强度因子随撑杆壁厚和穿透裂纹角度半宽值的变化规律,可为工程中管节点的止裂工作提供参考。

A number of different sizes of finite element models of tubular T-joints in jacket plat-forms were established,using the finite element software ANSYS,with a through-thickness crack at the weld toe of the brace.The load was axial force and in-plane bending moment,applying on the brace.Displacement extrapolation method was used to calculate stress intensity factor at the crack front.Firstly,the astringency of the results of stress intensity factor calculated by ANSYS was verified,with variation of the mesh size at the crack tip.Secondly,the influence of the wall thickness of brace and the angle half-width of through-thickness crack on stress intensity factor was discussed preliminary.The variation of stress intensity factor was obtained,with the wall thickness of brace and the angle half-width of through-thickness crack,to make some suggestions for the crack arrest of tubular joints in engineering.