Fatigue cracks increase structural failure risk and timely maintenance is very important. Maintenance planning is often formulated as a probabilistic optimization problem, considering uncertainties in structural and load modelling, material properties, damage measurements, etc. A decision rule or strategy, e.g. condition based maintenance (CBM), needs to be set up, and then an optimal maintenance criterion or threshold is derived via solving the optimization problem. This paper develops a probabilistic maintenance optimization approach exploiting value of information (VoI) computation and Bayesian decision optimization. The VoI based approach explicitly quantifies added values from future inspections, and gives an optimal decision (or strategy) by direct modelling decision alternatives and evaluating their expected outcomes, rather than a pre-defined strategy. A comparative study on VoI, life cycle cost (LCC) and reliability based optimization approaches is conducted. It is shown that the VoI based approach takes all available maintenance strategies into account (both with and without involving inspections), and can reliably yield optimal maintenance strategies, whether the VoI is larger than or equal to zero. When the VoI is equal to zero, LCC and reliability based CBM optimization can lead to suboptimal maintenance strategies. The differences in the approaches are illustrated on fatigue-sensitive components in a marine structure.

疲劳裂纹会增加结构失效的风险，及时维护非常重要。考虑到结构和载荷建模，材料特性，损伤测量等方面的不确定性，通常将维护计划表述为概率优化问题。需要设置决策规则或策略，例如基于条件的维护（CBM），然后通过解决优化问题得出最佳维护准则或阈值。本文开发了一种利用信息价值（VoI）计算和贝叶斯决策优化的概率维护优化方法。基于VoI的方法明确量化了未来检查的附加值，并通过直接建模决策备选方案并评估其预期结果来给出最佳决策（或策略），而不是预先定义的策略。对VoI，生命周期成本（LCC）和基于可靠性的优化方法进行了比较研究。结果表明，基于VoI的方法考虑了所有可用的维护策略（无论是否涉及检查），并且无论VoI大于或等于零，都可以可靠地得出最佳维护策略。当VoI等于零时，基于LCC和基于可靠性的CBM优化会导致次优维护策略。在海洋结构中对疲劳敏感的组件上说明了方法的差异。结果表明，基于VoI的方法考虑了所有可用的维护策略（无论是否涉及检查），并且无论VoI大于或等于零，都可以可靠地得出最佳维护策略。当VoI等于零时，基于LCC和基于可靠性的CBM优化会导致次优维护策略。在海洋结构中对疲劳敏感的组件上说明了方法的差异。结果表明，基于VoI的方法考虑了所有可用的维护策略（无论是否涉及检查），并且无论VoI大于或等于零，都可以可靠地得出最佳维护策略。当VoI等于零时，基于LCC和基于可靠性的CBM优化会导致次优维护策略。在海洋结构中对疲劳敏感的组件上说明了方法的差异。