In this paper, an unavailability model is proposed to define the test and maintenance policies of systems that are subject to hidden failure and degradation, assuming practices of continuous improvement (CI) under imperfect maintenance actions with Proportional Age Setback (PAS) and Proportional Age Reduction (PAR). For this, two CI equations are analyzed to estimate the progress of maintenance effectiveness over time, and a maximum unavailability constraint is incorporated into the model for evaluation of safety point of view. A numerical application was performed, and the results showed that by adopting CI practices over maintenance actions, the unavailability of the system is reduced in greater proportion over time, besides contributing positively to safety.

在本文中，提出了一种不可用性模型来定义受隐藏故障和退化影响的系统的测试和维护策略，并假设在不完善的维护操作下采用比例年龄挫折（PAS）和比例年龄减少的持续改进（CI）的做法（PAR）。为此，分析了两个CI方程以估计维护有效性随时间的进展，并将最大不可用性约束纳入模型中以评估安全性观点。进行了一个数值应用，结果表明，通过在维护操作中采用CI做法，除对安全性做出了积极贡献外，随着时间的流逝，系统的不可用性将以更大的比例减少。