Spatial Model for Corrosion in Ships and FPSOs
Spatial Model for Corrosion in Ships and FPSOs
复制标题
船舶和 FPSO 腐蚀空间模型
DOI：
--
复制
发表时间：
2014
期刊：
影响因子：
--
通讯作者：
D. Štraub
中科院分区：
文献类型：
--
作者：
J. Luque;R. Hamann;D. Štraub
船舶结构的腐蚀受到多种因素的影响，这些因素随时间和空间的变化而变化。实践中使用的现有腐蚀模型仅部分地解决了腐蚀过程的空间变异性。典型的腐蚀参数估计是基于对来自不同船舶和操作条件的结构元件的平均测量，而没有考虑元件之间和内部的可变性。然而，在确定必要的检查范围时，这种可变性很重要，它可能影响船舶结构的可靠性。我们开发了一个基于分层方法的概率时空腐蚀模型，它代表了腐蚀过程的空间变异性。该模型包括容器-隔间-框架-结构单元-板单元等层次。在各个层次上，都引入了代表共同影响因素的变量。此外，在最低水平，即板单元，腐蚀过程被建模为一个空间随机场。为了便于说明，该模型通过贝叶斯分析与一组油轮的测量数据进行训练。在此应用中，发现船舶不同部位的腐蚀过程之间存在显著的空间依赖性，所提出的分层模型可以捕捉到这一点。最后，演示了在对船舶的未来状况进行推断时如何利用这种空间依赖性。
Corrosion in ship structures is influenced by a variety of factors that are varying in time and space. Existing corrosion models used in practice only partially address the spatial variability of the corrosion process. Typical estimations of corrosion parameters are based on averaging measurements over structural elements from different ships and operational conditions, without considering the variability among and within the elements. However, this variability is important when determining the necessary inspection coverage, and it may influence the reliability of the ship structure. We develop a probabilistic spatio-temporal corrosion model based on a hierarchical approach, which represents the spatial variability of the corrosion process. The model includes the hierarchical levels vessel – compartment – frame – structural element – plate element. At all levels, variables representing common influencing factors are introduced. Moreover, at the lowest level, which is the one of the plate element, the corrosion process is modeled as a spatial random field. For illustrative purposes, the model is trained through Bayesian analysis with measurement data from a group of tankers. In this application it is found that there is significant spatial dependence among corrosion processes in different parts of the ships, which the proposed hierarchical model can capture. Finally, it is demonstrated how this spatial dependence can be exploited when making inference on the future condition of the ships.