基于有限差分法的复合系泊链缆动力模型及其验证

具有链—缆—链结构的复合系泊链缆因其相对于全钢链质量和成本上的优势而在深水系泊中得以广泛应用。基于细长杆理论采用有限差分法建立了可以考虑链—缆—链结构的复合系泊缆数值模型，将其应用于不同工况下全钢链和复合链缆运动的数值模拟中，并开展了验证。首先，将单根钢链顶张力数值模拟结果与不同工况下的模型试验结果进行了对比，验证了数值预报程序应用于全钢链的准确性。然后，对于复合系泊链缆开展了静刚度和动刚度迭代数值模拟，并将模拟结果同已发表文章中的算例结果进行比较，验证了该数值模型在复合链缆模拟上的准确性。发现对于单根钢锚链的验证，激励半径越大，激励周期越小，一个周期内顶张力幅值及其极差越大，钢链运动就越剧烈。对于链—缆—链式复合系泊链缆的验证，发现静刚度迭代中数值模拟结果与算例结果差异较小；对于动刚度迭代，除个别大幅慢漂工况外，两者有较高的吻合；且激励周期越小，激励半径越大，复合系泊链缆顶张力越大，弹性模量越小，运动越剧烈。对于聚酯缆刚度的敏感性分析，发现改变动刚度经验公式参数的情况下，杨氏模量的静刚度迭代和动刚度迭代结果误差分别最大达到了60.81%和68.21%，因此合成纤维材料特性对复合系泊链...

Development and validation of the dynamic model of hybrid synthetic mooring lines based on finite difference method

The hybrid synthetic mooring line with chain-cable-chain structure is widely used in deep-water mooring because of its advantages in weight and cost compared with the all-steel chain. In this study, a numerical model of composite mooring cable with chain-cable-chain structure is established based on the proposed finite difference model, and applied to the numerical simulation of both the steel chain and the hybrid synthetic mooring line under different calculation cases. Firstly, the numerical simulation results of the top tension of a single steel chain are compared with the model test results under different cases to verify the accuracy of the proposed numerical model of the steel chain. Then, for the hybrid synthetic mooring line, the numerical simulation of the composite cable is carried out considering static and dynamic stiffness iterations, and the simulation results are compared with the results in the published papers to verify the accuracy of the numerical model in the simulation of the hybrid synthetic mooring line. For the verification of a single steel mooring chain, it is found that the larger the excitation radius and the smaller the excitation period, the larger the top tension amplitude and its extreme difference in one cycle, and the more violent the steel chain motion. For the verification of the chain-cable-chain composite mooring chain and cable, it is found that the difference between the numerical simulation results and the numerical example results in the static stiffness iteration was small. For the dynamic stiffness iterations, except for some large slow drift conditions, there is a high agreement between the two. And the smaller the excitation period and the larger the excitation radius, the higher the top tension of the composite mooring chain cable, the smaller the elastic modulus and the more violent the motion. For the sensitivity analysis of polyester cable stiffness, it is found that the error of static stiffness iteration and dynamic stiffness iteration results of Young''s modulus reaches the maximum of 60.81% and 68.21% respectively when changing the parameters of the empirical equation of dynamic stiffness, so the synthetic fiber material properties have a large impact on stiffness performance of the composite mooring chain cable.