张紧式锚泊系统松弛-张紧过程冲击张力分析

Analysis of snap loading of a taut mooring system in the slack-taut process

张紧式锚泊系统在随浮体运动过程中可能会出现松弛-张紧状态的交替转化,导致锚泊线内动张力幅值显著提升。基于锚泊线动力有限元分析模型,通过对锚泊线顶端施加一系列不同幅值与频率的正弦激励,对松弛-张紧过程中的张力变化规律进行总结和比较。结果表明:顶端激励达到特定的幅值与频率时锚泊线会发生松弛-张紧现象,其动张力最小值接近零,最大值可达到预张力的若干倍;频谱分析显示其频率成分中出现除激励频率外的倍频和高频成分。该研究结果对进一步探究冲击张力的产生机理及锚泊系统的设计具有参考意义。

A taut mooring system may cause slack-taut alternative transformation with the motion of a floating body, which could result in the significant increase in dynamic tension amplitude in the mooring line. On the basis of the dynamic finite element analysis model, a series of sinusoidal excitation with different amplitudes and frequencies added to the upper end of the mooring line. Moreover, the change laws of dynamic tension in the slack-taut process are summarized and compared. The results indicated that the slack-taut phenomenon could occur in the mooring line when the amplitude and frequency of excitation reach a certain value. The minimum dynamic tension close to zero, and the maximum dynamic tension reach up to several times of pretension. The spectral analysis of dynamic tension shows that frequency doubling, and high-frequency components appear in addition to the frequency of excitation. The results could be used as reference for further investigation of the mechanism of snap loading, and the design of a mooring system.