基于动态刚度模型的聚酯缆力学性能研究

Research on the Mechanical Performance of Polyester RopeBased on the Dynamic Stiffness Model

采用聚酯缆作为系泊材料的张紧式系泊形式,克服了锚链自重大的缺点,为浮体提供了更好的系泊性能,在深水系泊领域备受关注。聚酯缆的非线性力学性能明显,其非线性本构关系使得该材料的张力响应预测难度增大。因此,精确模拟该关系具有重要意义。本文基于绝对节点坐标法,在轴向大拉伸的情况下,结合8股编织结构的聚酯缆的动态刚度模型,开展聚酯缆张力响应精确计算与分析,并与近似算法对比。研究结果表明,采用精确算法得到的聚酯缆轴向张力高于近似算法,聚酯缆的非线性本构关系使其“越拉越刚”,近似计算可能会使得张力预测失真。因此,在计算使用聚酯缆材料的系泊系统的张力响应时,采用精确的动态刚度计算模型是十分必要的。

The taut mooring system using polyester rope as the mooring lines overcomes the heavy weight of the traditional chain mooring material and provides better mooring performance for the floating structures,which attracts much attention in the field of deep-water mooring.The nonlinear mechanical properties of the polyester make it more difficult to predict the tension response of the material.Therefore,it is essential to model this nonlinear relationship accurately.In this paper,based on the absolute nodal coordinate formulation under the condition of large axial tension and combined with the dynamic stiffness model of 8-strand braided polyester rope,the tension response of the polyester line is accurately calculated and analyzed.The results are compared with the approximate method.The simulation shows that the axial tension of the polyester cable obtained by the accurate model is larger than that of the approximate method.The nonlinear constitutive relationship of the polyester cable displays the phenomenon that the larger stretch,the larger sitffness is.Besides,the approximate method will distort the tension prediction.Therefore,it is necessary to adopt an accurate dynamic stiffness model in calculating the tension response of mooring systems using polyester material.