一种新的海洋平台管节点应力评估方法

A new method for stress analysis of tubular joints in offshore platform

海洋工程焊接管节点受应力集中及复杂随机载荷的联合作用,容易发生疲劳破坏。为了提高焊接管节点结构疲劳寿命预测的准确性,文章以管壁厚方向上的一点作为疲劳评估点,提出了一种新的管节点结构应力计算方法。通过与国际上公开发表的疲劳试验数据进行比较,证明了文中方法应用于管节点结构的可行性及考虑壁厚方向应力梯度的有效性。基于数值计算,文中还提出了可用于T型管节点应力集中系数计算的参数公式,并对参数公式的精度进行了验证。

Fatigue damage in welded tubular joints is almost unavoidable due to combined effect of stress concentration and random stresses. To improve accuracy of fatigue life estimation of welded tubular joints, a new structural stress approach for tubular joints is proposed, where a point below the outer surface along the wall thickness direction is adopted as the fatigue assessment point. The applicability and correctness of the new method for fatigue strength assessment of tubular joints, as well as its effectiveness in considering the stress gradient along the wall thickness, are verified by comparing the numerical results with published experimental data of fatigue tests. Based on finite element analysis, parametric equations are derived for calculating stress concentration factors at all angular positions along the intersection of tubular T-joints. The accuracy of the parametric equations is finally validated.