Reliability Assessment of Inspected Marine Structure

本文提出了一种贝叶斯可靠性分析方法，利用在役检验过程中收集的数据，建立了多构件海洋结构的最优检验计划。推导了在检查时发生的各种事件的概率的表达式。在这些概率的基础上，确定了后验置信度和贝叶斯期望可靠性。根据计算的可靠性，确定下一次检查的最佳时间。上面提到的表达式对于有关检查结果的清晰信息很有用。例如，需要检测到的裂纹的确切大小来估计可能性。如果只有模糊信息可用，则不能应用该方法。因此，本文还尝试了一种模糊-贝叶斯可靠性方法来确定合适的检查计划以保持结构的完整性。结果表明，该方法能很好地确定不确定因素的后验密度。

This study develops a method of Bayesian reliability analysis to establish an optimal inspection scchedule of marine stuctures with multiple components using the data collected during inservice inspections. Expressions for the probabilities of various events that take place at the time of an inspection are derived. On the basis of these probabilities, the posterior degree of belief and Bayesian expected reliability are determined. From the computed relliability, the optimum time of the next inspection is determined. The above mentioned expressions are useful with crisp information about the inspection results. For example, the exact size of the detected crack is needed to estimate the likelyhood. the method cannot be applied if there is only fuzzy information avvailable. Therefore, a fuzzy-Bayesian reliability approach for the decision of proper inspection schedule to maintain structural integrity is also tried in this study. It is found out that the posterior density of uncertain factors is very well defined by the proposed method.