Abstract The nonlinear oscillations of the floating structures anchored by cables are studied in three dimensions. The floating structure is anchored by four symmetric mooring lines and the mooring lines are fixed on the seafloor at the other ends. The stiffness matrix of 3D cable element has been established and applied to analyze the dynamics of the 3D floating structures anchored by cables. The complex compatibility conditions which relate the responses of the floating body and cables have been proposed. The equations of motion for the mooring lines and floating body are individually formulated. Then they are combined as an entire system by utilizing the compatibility conditions. At last, the entire system is analyzed numerically with horizontal harmonic excitations applied on the floating body. The amplitudes for both the responses of the platform and the maximum mooring force are studied as the excitation frequency changes. The responses of the platform and the maximum mooring force are also investigated for varieties of cable parameters.

中文翻译：

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缆索系泊海上结构的 3D 非线性动力分析

摘要 从三个维度研究了索锚浮式结构的非线性振动问题。浮动结构由四根对称的系泊绳锚固，系泊绳的另一端固定在海底。建立了 3D 索单元的刚度矩阵，并将其应用于分析由索锚定的 3D 浮动结构的动力学。提出了与浮体和电缆响应相关的复杂兼容性条件。系泊缆绳和浮体的运动方程是单独制定的。然后利用兼容性条件将它们组合为一个完整的系统。最后，对浮体施加水平谐波激励对整个系统进行数值分析。随着激励频率的变化，研究了平台响应和最大系泊力的振幅。平台的响应和最大系泊力也针对各种电缆参数进行了研究。