自保护技术作为自愈技术的一种,能够使系统在环境或工况条件变化的干扰下以较高可靠性运行。本文构建了一个新的具有相依主要部件和辅助部件的系统可靠性模型,其中主要部件的退化速率与工作中的辅助部件的数量有关。此外,基于定期检测

For artificial systems, the rising cost and inaccessible scenes for maintenance have increased the need of self-healing, which intends to give systems the ability to heal the damage and faults without external intervention like living organisms. Although self-healing techniques have been widely studied and applied in many engineering systems, reliability research for such systems is limited. Besides, the self-healing ability of artificial systems is generally derived from self-healing resources embedded in the system, while the limitations of embedded resources have less been considered in related research. To fill the research gap, in this paper we consider systems operating under shock environments with limited self-healing resources. Two self-healing policies are designed for allocating the limited resources and enhancing the system reliability. Under different policies, new reliability models are developed and a recursive method is proposed to evaluate the system reliability. Further, some new indexes are introduced and derived for evaluating the performance of the self-healing policies. Based on the new indexes, numerical examples are presented in the end to compare the two policies. © 2023

In many engineering systems, aside from the main component fulfilling the essential functions, a number of auxiliary components are configured to protect the main component and improve the reliability of the system. In actual operation, the failure or state change of the auxiliary components may affect the reliability both the main component and the remaining operational auxiliary components. However, the structure and dependence between the auxiliary components has been ignored in the existing studies. To fill this gap, we consider a system with a main component and a protective auxiliary subsystem. The latter is a load-sharing k out-of -n system, that is, there is dependence between the auxiliary components. For such a system, an opportunistic inspection and preventive maintenance strategy is proposed. Then, we derive the system reliability using the Laplace transforms and the matrix method. The long-run average cost of the system is then derived, based on which the optimal maintenance problem is formulated and solved by an enumeration method. A numerical example, together with sensitivity studies of some model parameters, shows how the evolution of the parameters influences the optimal maintenance strategy. Finally, the model is extended by introducing periodic inspection and preventive maintenance strategy for main component, and the two strategies are compared.

To maintain a multi-component system, different dedicated service teams with different skill sets and tools are often involved. Such a relationship constitutes maintenance team coalition. In most cases, it may not be the best to plan each team's maintenance activities independently as such independent decisions may not achieve the required system-level reliability performance (RP). To balance the reliability and costs of components in achieving a high level of system RP, an efficient method is to assign a failure penalty cost to each maintenance team and then develop their optimal maintenance policy. In this article, the Shapley value is utilized for fair penalty costs allocation to avoid any interest for teams to secede the coalition, whose actual role is to evaluate the criticality level of each component in the context of coalition. Moreover, imperfect inspection and imperfect repair are quite common in practice because of limited resources, technologies and time. To address these practical concerns, a new reliability-centered hybrid preventive maintenance policy is proposed. The optimal inspection interval and age-based replacement interval are determined for each team to minimize the cost rate over an infinite time horizon. Several numerical examples illustrate that the proposed decision-making method is effective in handling such complex maintenance problems involving a coalition of dedicated maintenance teams.

Nowadays, the post-sale warranty has become a crucial marketing strategy, and how to design and determine the optimal warranty policy has become one of the important issues for manufacturers. In the existing literature, warranty design and optimization mainly focus on one-dimensional and two-dimensional policies. However, as competition intensifies and customer requirements increase, product warranty terms usually involve three or more factors. In this paper, we propose a three-dimensional warranty policy for repairable products, in which limitations on failure time, repair time, and repair number are integrated. Considering the conflict between manufacturers and consumers, a novel renewable combination replacement warranty is further designed. By developing the corresponding sale price and warranty cost models, a profit optimization model is proposed. From the manufacturer's perspective, the optimal warranty policy is obtained by maximizing the expected profit. A numerical example with sensitivity analysis and comparison studies is conducted to illustrate the proposed model. The results show that the proposed warranty policy can make the manufacturer more profitable and help to reduce the conflict between the manufacturer and the consumer.

在系统运行期间,通过检测发现系统的缺陷状态,在其未失效时提前采取预防性维修措施,可以有效减少失效带来的严重后果。检测通常是不完美的,且检测误差概率是非恒定的;当检测显示系统处于缺陷状态,进行最小维修,且限制最小维修的次数,当

In many complex industrial systems, failures are not always evident to the operating crew, thus inspections are used to identify such hidden failures and then make necessary maintenance actions. In this paper, we study a two-stage system that is subject to two competing risks of degradation and random shocks. Failures of this two-stage competing-risk system are hidden and could only be detected by periodic inspections. For such a system, a delay-time model is introduced to describe the evolution of the system behavior. Random shocks are assumed to follow a homogeneous Poisson process. A preventive maintenance policy is presented in response to the observed system state, based on which the expected cost rate of the system is derived. This paper aims to find the minimal expected cost rate by determining the optimal inspection interval. A numerical example is presented to demonstrate the applicability of the proposed method and results.
© 2021 Elsevier Ltd

复杂工业系统的故障中有40%属于隐藏故障,若隐藏故障得不到及时消除,则可能导致巨大的经济损失。本文针对具有隐藏故障的多状态竞争失效系统,在考虑不完全检测的基础上,对其进行了维修建模。首先,基于制定的视情维修策略,分析了系统的

The complexity of dependence between different types of components results in many challenges to estimate system reliability and to optimize maintenance plans. In this paper, we develop a reliability model to study the failure dependence of a system with a main component and several protective auxiliary components. Damage to the main component caused by random environmental shocks depends on the number of auxiliary components in operation. When the execution of inspection and maintenance actions during system operation is difficult, failures of the main component provide opportunities to inspect and replace the auxiliary components. We derive the system reliability using Laplace transforms and the matrix method. The optimization problem is solved by an enumeration method. A numerical example and sensitivity studies of cost parameters show how the evolution of the parameters influences the optimal maintenance strategy. The results show that a high replacement threshold of the auxiliary components is required when the replacement cost of the main component is high. Conversely, the threshold could be adjusted to a lower level when the replacement cost of the auxiliary components and the downtime cost increase.
© The Author(s) 2020. Published by Oxford University Press on behalf of the Institute of Mathematics and its Applications. All rights reserved.