Abstract This paper develops a new joint representation to indicate the nonlinear load-deformation behavior and ultimate strength of FG K joints in the global pushover analysis. To simulate the ductile fracture of FG K joints, the study establishes the fracture locus of steel S355 and incorporates the fracture locus into the Johnson-Cook model for fracture simulation. The joint representation is developed through regression analyses of the FE results with/without fracture simulation and validated against the reported test data. The load-deformation formulation and ultimate strength equation are functions dependent on the geometric parameters, covering the brace to chord diameter ratio β from 0.4 to 1.0 and the chord diameter to thickness ratio 2γ from 20 to 50. The study finally implements the local joint behavior into the pushover analysis of a 3D jacket platform to evaluate the overall performance after grouting the critical joints. The proposed load-deformation formulation and ultimate strength equation prove to be effective in representing the local FG K joints in the frame analysis.

中文翻译：

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Pushover 分析中完全灌浆 K 节点非线性行为的表示

摘要 本文开发了一种新的关节表示法，以在全局推覆分析中指示 FG K 关节的非线性载荷-变形行为和极限强度。为了模拟FG K接头的韧性断裂，研究建立了S355钢的断裂轨迹，并将断裂轨迹纳入Johnson-Cook模型进行断裂模拟。联合表示是通过使用/不使用断裂模拟的有限元结果的回归分析开发的，并根据报告的测试数据进行验证。载荷-变形公式和极限强度方程是依赖于几何参数的函数，涵盖了从 0.4 到 1.0 的支撑与弦杆直径比 β 和从 20 到 50 的弦杆直径与厚度比 2γ。该研究最终将局部接缝行为应用到 3D 导管架平台的推覆分析中，以评估关键接缝灌浆后的整体性能。所提出的载荷-变形公式和极限强度方程被证明可以有效地表示框架分析中的局部 FG K 接头。