深水脐带缆结构阻尼的数值与试验研究

深水动态脐带缆内部结构复杂，其阻尼特性对脐带缆的舞动以及疲劳损伤有着重要的影响。脐带缆在和流体相互作用过程中，脐带缆内部构件可能会产生滑动，进而影响脐带缆的结构阻尼，这也使得真实海况中脐带缆的舞动和疲劳是一项复杂而值得深入研究的课题。为验证有限元模型能够很好地模拟脐带缆的结构阻尼特性，在考虑内部结构单元间摩擦的基础上，利用ANSYS建立了用于中国南海某油田的脐带缆多层滑移接触摩擦模型。同时，采用自由衰减法对该动态脐带缆开展了原型试验，测得了该缆的结构阻尼比与自振周期。通过对比有限元模型计算结果与原型试验结果发现：数值模型获得的该脐带缆的结构阻尼值与试验值非常接近，这为工程中获得脐带缆结构阻尼比的值提供了好的方向。

Numerical and experimental study on damping of deepwater umbilical cable structures

The inner structure of a deep-water dynamic umbilical cable is complicated, and its damping capabilities greatly impact the umbilical cable''s galloping and fatigue damage. The internal sections of the umbilical cable may move during the contact between the umbilical cable and the fluid, which will have an influence on the structural damping of the umbilical cable. Additionally, this makes the galloping and wear and tear of the umbilical cable in actual sea conditions a difficult problem deserving in-depth analysis. A multi-layer sliding contact friction model of the umbilical cable used in an oilfield in the South China Sea was established by using ANSYS in order to confirm that the finite element model can accurately simulate the structural damping characteristics of the umbilical cable on the basis of taking into consideration the friction between internal structural elements. In parallel, the structural damping ratio and the natural vibration period of the dynamic umbilical cable were analyzed as part of the prototype experiment utilizing the free attenuation approach. The structural damping value of the umbilical cable derived by the numerical model was found to be extremely close to the experimental value, which gives a suitable direction for estimating the structural damping ratio of the umbilical cable in engineering. This was identified by comparing the estimated results of the finite element model with the prototype experimental findings.