一种新开发的ANCF缆索单元

A Newly Developed ANCF Cable Element

为精确模拟系浮系统中系留缆索的动力学行为,应用绝对节点坐标公式(absolute nodal coordinate formulation,ANCF),开发一种新的ANCF缆索单元。该单元考虑了缆索的层级数目、各层材料的力学性能,并通过子域划分来更好地适应材料的层间差异。其中,利用Kelvin-Voigt模型来解释内芯层的黏弹性性质,而将改进后的Yeoh模型应用于护套层当中以更好地契合材料的超弹性性能。此外,设计一种具有隐式效果的差分格式对动力学微分方程组进行数值求解。最后,通过一系列静力学与动力学数值计算证明单元的精度与收敛特性,并对比几种应用不同超弹性模型的ANCF单元,证实应用改进的Yeoh模型的ANCF单元的合理性与优越性。

In order to simulate the dynamic behavior of tether cables in tethered system,a new ANCF cable element was proposed by using the absolute nodal coordinate formulation(ANCF).The number of layers of cables and the mechanical properties of materials in each layer all were considered in the element.The Kelvin-Voigt model was used to explain the viscoelastic properties of the inner core layer,and the improved Yeoh model was applied to the sheath layer to explain the hyperelastic properties of materials.Moreover,a difference scheme with implicit effect was designed to solve the dynamic differential equation numerically.Finally,the accuracy and convergence of element were proved by a series of static and dynamic numerical calculations,and the ANCF elements using several different hyperelastic materials were compared,which proved the rationality and superiority of the ANCF cable element using the improved Yeoh model.