Rapid evaluation method for ultimate bearing capacity of circular hollow section gap K-joints with localized corrosion under anti-symmetric axial loading

초록

Circular hollow section gap K-joints (CHS gap K-joints) are widely used in marine structures. However, exposure to harsh marine environments leads to corrosion, which degrades mechanical performance and reduces structural safety. This study establishes methods for evaluating the ultimate bearing capacity of corroded K-joints. First, a refined finite element model was established by modifying element thickness. The model was validated against experimental loading tests of corroded K-joints, confirming its accuracy. Random corrosion models and corrosion size parameters were analyzed to identify corrosion-sensitive regions affecting ultimate bearing capacity. The Sobol sensitivity analysis was conducted on geometric and corrosion parameters, yielding sensitivity coefficients and identifying key parameters influencing ultimate bearing capacity degradation. Based on the theoretical failure modes of K-joints, and considering the combined effects of discretely distributed corrosion and different loading cases, analytical formulas were established to predict the ultimate bearing capacity and corresponding failure modes of corroded K-joints. These formulas provide a technical basis for assessing the safety of corroded circular hollow section gap K-joints and similar joints.

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