For the systems that experience competing failure processes, an uncertain process–based degradation model is developed to describe the systems. The competing degradation process is composed of internal continuous degradation and external shocks, and the mutual dependence between them is considered. When the magnitude of the internal degradation exceeds the threshold, the soft failure occurs. While for the shock processes involving the randomness and the subjective information, we adopt the uncertain random renewal reward process to characterize it. Hard failure occurs when the damage of the shock process exceeds the strength threshold of the system. By using the belief reliability metric, the reliability of the degraded system is defined as the chance measure that neither soft failure nor hard failure occurs. And the effect of the degradation-shock dependence on the system reliability is performed by the parametric studies. Then the proposed degradation model is introduced into the preventive maintenance strategy to minimize the average maintenance cost. Using the microelectromechanical systems as an example, the effectiveness of the constructed degradation model and maintenance strategy is illustrated, and the proposed model can characterize the system degradation process in a superior way to the stochastic process model. These methods can be applied to other similar degraded systems and provide support for maintenance decisions.

中文翻译：

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在相互依赖的退化和冲击过程中，基于不确定过程的系统可靠性和维护建模

对于经历竞争性故障过程的系统，开发了一个基于不确定过程的退化模型来描述系统。竞争退化过程由内部持续退化和外部冲击组成，考虑了它们之间的相互依赖。当内部退化的幅度超过阈值时，就会发生软故障。而对于涉及随机性和主观信息的冲击过程，我们采用不确定的随机更新奖励过程来表征。当冲击过程的破坏超过系统的强度阈值时，就会发生硬失效。通过使用置信可靠性度量，退化系统的可靠性被定义为既不发生软故障也不发生硬故障的机会度量。退化冲击依赖对系统可靠性的影响是通过参数研究来实现的。然后将所提出的退化模型引入到预防性维护策略中，以最小化平均维护成本。以微机电系统为例，说明了所构建的退化模型和维护策略的有效性，并且所提出的模型能够以优于随机过程模型的方式表征系统退化过程。这些方法可以应用于其他类似的降级系统，并为维护决策提供支持。以微机电系统为例，说明了所构建的退化模型和维护策略的有效性，并且所提出的模型能够以优于随机过程模型的方式表征系统退化过程。这些方法可以应用于其他类似的降级系统，并为维护决策提供支持。以微机电系统为例，说明了所构建的退化模型和维护策略的有效性，并且所提出的模型能够以优于随机过程模型的方式表征系统退化过程。这些方法可以应用于其他类似的降级系统，并为维护决策提供支持。