轴向载荷下多平面DT型管节点应力集中系数研究

Numerical analysis on stress concentration factor for multi-planar tubular DT-joints under axial loading

应力集中系数对于海洋平台结构中管节点的疲劳寿命评估至关重要。文章以多平面DT型管节点为研究对象,采用有限元方法分析了轴向载荷作用下沿其弦管—撑管相贯线焊缝的应力集中系数分布。在保证计算精度的前提下尽量减少网格数量,采用分区网格划分方法进行管节点建模。基于有限元分析结果,研究了不同几何形状参数对应力集中系数分布变化规律的影响,拟合得到一组应力集中系数参数公式,并通过两种相对误差验证了该参数公式的有效性。

The stress concentration factor(SCF) plays an important role in fatigue life assessment of tubular joints in offshore structures. In this study, finite element(FE) method was employed to investigate the SCF distributions along the chord-brace intersection of multi-planar DT-joints under axial loading. In order to guarantee good quality and appropriate quantity of FE meshes, a method of sub-zone mesh generation was adopted. The effects of geometrical parameters on the SCF distributions were investigated. A set of parametric equations was proposed based on the results of the FE analysis. Two types of error analysis were used to verify the reliability of developed equations.