In this study, for efficient safety assessment of a ship’s hull girder subjected to a combination of the global vertical bending moment (VBM) and the local double-bottom bending moment (DBM), a numerical method based on a coupled computational fluid dynamics (CFD) and finite-element analysis (FEA) is first developed. The mutual two-way coupled CFD and FEA in which the elastic deformation of the ship is taken over to the CFD solutions is employed. The present two-way coupled method is developed in two steps, in a weakly coupled manner and a strongly coupled manner. The developed two-way coupled methods are validated via a comparative study against the available experimental results and the straightforward one-way coupled CFD and FEA in terms of the rigid body motion, VBM, and local water pressure. Using the present strongly coupled method, the added mass with regards to the elastic deformation of the ship is reflected in the results of a decrease in the frequency of 2-node vibration mode of the ship or the vibratory (hydroelastic) component in the water pressure. Then, the DBM is evaluated using the estimated water pressure on the ship bottom. An investigation is finally made into the effect of the hydroelastic component in the DBM on the total DBM and the hull girder ultimate strength.

中文翻译：

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基于双向耦合 CFD 和 FEA 的大型集装箱船整体和局部水弹性响应的数值研究

在这项研究中，为了有效评估受全局垂直弯矩 (VBM) 和局部双底弯矩 (DBM) 组合影响的船体梁，采用了一种基于耦合计算流体动力学 (CFD) 的数值方法) 和有限元分析 (FEA) 是首次开发的。采用双向耦合的 CFD 和 FEA，其中将船舶的弹性变形转移到 CFD 解决方案中。本双向耦合方法分两步发展，弱耦合方式和强耦合方式。所开发的双向耦合方法通过与可用实验结果和直接单向耦合 CFD 和 FEA 在刚体运动、VBM 和局部水压方面的比较研究得到验证。使用目前的强耦合方法，与船舶弹性变形相关的附加质量反映在船舶二节点振动模式频率或水压中的振动（水弹性）分量降低的结果中。然后，使用估计的船底水压评估 DBM。最后研究了 DBM 中的水弹性成分对总 DBM 和船体梁极限强度的影响。