非线弹性系泊缆系泊性能

针对材料特性为非线性的纤维缆,使用有限元法建立了非线弹性缆索方程的数值模型.在不同水深情况下,针对不同材料的4点系泊系统,通过分析比较浮体最大允许位移内各系泊系统的位移-回复力关系,以及缆索上端点水平张力占总张力的比重,得到使用轻质纤维缆的张紧系泊系统在深水环境下较其他形式的系泊系统具有优势.对材料特性为非线弹性的聚酯纤维缆计算缆上端点的张力,材料特性使用线性的应力应变关系拟合非线性特性,其结果与采用非弹线性模型的相应结果进行对比,发现线性化的拟合计算不能真实反映缆索内的实际张力情况,说明了使用非线弹性模型的必要性.以一Spar的系泊系统为例,分析了3种轻质纤维缆的动力特性差异,发现使用聚酯纤维能得到更好的系泊性能.

Mooring Performance of Nonlinear Elastic Mooring Lines

A numerical model was established using finite element method in time domain for fiber mooring lines. For different water depths, the displacement lateral force relations were compared for three types of mooring system and the corresponding effective utilization rates were calculated. This shows that it is more competitive for the taut mooring system using light weight fiber lines than the other ones in deep water. The dynamic analysis of the polyester mooring line was conducted, where a linear material property was proposed to fit the nonlinear stress strain relations, the result was compared with the nonlinear elastic model. It was found that the simulation by linear fitting to the material properties in the numerical model can not obtain a reasonable result and it is necessary to use nonlinear elastic model for fiber lines. For the mooring system of a Spar, three types of fiber lines were used respectively. Dynamic analysis was performed and all tensions of the three type lines were compared. The results show that polyester mooring lines present the best performance.