海上三维管式KT型节点外支架应力集中系数疲劳设计公式

对3种不同轴向加载条件下三维直角管式KT型节点的应力集中系数(SCF)进行了一系列参数分析。三维KT型节点是六腿海上导管架结构的一种重要的节点形式,用于连接支撑构件和导管架的主支架。分析结果用于描述几何特性和加载条件对主(外)支架不同位置处SCF的影响。基于经试验数据验证的有限元分析结果,研发出一套完整的SCF数据库;然后经过非线性回归分析,建立了新的SCF方程,用于3种不同加载条件下三维KT型节点疲劳设计。英国能源部(DoE)利用试验数据对这些方程进行了评估,并给出其适用范围。

The Development of Fatigue Design Formulas for the Outer Brace SCFs in Offshore Three-Planar Tubular KT-Joints

A set of parametric stress concentration factor (SCF) analyses is carried out in the present research for right-angle three-planar tubular KT-joints under three different axial loading conditions. Three-planar KT-joints are one of the most important joint types in the six-legged offshore jacket-type structures since they connect the bracing members to the main legs of the jacket template. The analysis results are used to present general remarks on the effect of geometrical characteristics and loading conditions on the SCFs at different saddle positions on the main (outer) braces. Based on the results of FE analyses which are verified against the experimental data, a complete set of SCF databases is developed. Afterwards, through nonlinear regression analysis, a new set of SCF design equations is established for the fatigue design of three-planar KT-joints under three different axial load cases. An assessment study of these equations is conducted against the experimental data and the acceptance criteria proposed by the UK Department of Energy (DoE).