Linking component importance to optimisation of preventive maintenance policy

In reliability engineering, time on performing preventive maintenance (PM) on a component in a system may affect system availability if system operation needs stopping for PM. To avoid such an availability reduction, one may adopt the following method: if a component fails, PM is carried out on a number of the other components while the failed component is being repaired. This ensures PM does not take system’s operating time. However, this raises a question: Which components should be selected for PM? This paper introduces an importance measure, called Component Maintenance Priority (CMP), which is used to select components for PM. The paper then compares the CMP with other importance measures and studies the properties of the CMP. Numerical examples are given to show the validity of the CMP

Generalized integrated importance measure for system performance evaluation: application to a propeller plane system

The integrated importance measure (IIM) evaluates the rate of system performance change due to a component changing from one state to another. The IIM simply considers the scenarios where the transition rate of a component from one state to another is constant. This may contradict the assumption of the degradation, based on which system performance is degrading and therefore the transition rate may be increasing over time. The Weibull distribution describes the life of a component, which has been used in many different engineering applications to model complex data sets. This paper extends the IIM to a new importance measure that considers the scenarios where the transition rate of a component degrading from one state to another is a time-dependent function under the Weibull distribution. It considers the conditional probability distribution of a component sojourning at a state is the Weibull distribution, given the next state that component will jump to. The research on the new importance measure can identify the most important component during three different time periods of the system lifetime, which is corresponding to the characteristics of Weibull distributions. For illustration, the paper then derives some probabilistic properties and applies the extended importance measure to a real-world example (i.e., a propeller plane system)

Opportunistic Maintenance Strategy of a Heave Compensation System for Expected Performance Degradation

In the marine industry, heave compensation systems are applied to marine equipment to compensate for the adverse effects of waves and the hydraulic system is usually used as the power system of heave compensation systems. This article introduces importance theory to the opportunistic maintenance (OM) strategy to provide guidance for the maintenance of heave compensation systems. The working principle of a semi-active heave compensation system and the specific working states of its hydraulic components are also first explained. Opportunistic maintenance is applied to the semi-active heave compensation system. Moreover, the joint integrated importance measure (JIIM) between different components at different moments is analyzed and used as the basis for the selection of components on which to perform PM, with the ultimate goal of delaying the degradation of the expected performance of the system. Finally, compared with conditional marginal reliability importance (CMRI)-based OM, the effectiveness of JIIM-based OM is verified by the Monte Carlo method

Importance Measure-Based Maintenance Strategy Considering Maintenance Costs

Maintenance is an important way to ensure the best performance of repairable systems. This paper considers how to reduce system maintenance cost while ensuring consistent system performance. Due to budget constraints, preventive maintenance (PM) can be done on only some of the system components. Also, different selections of components to be maintained can have markedly different effects on system performance. On the basis of the above issues, this paper proposes an importance-based maintenance priority (IBMP) model to guide the selection of PM components. Then the model is extended to find the degree of correlation between two components to be maintained and a joint importance-based maintenance priority (JIBMP) model to guide the selection of opportunistic maintenance (OM) components is proposed. Also, optimization strategies under various conditions are proposed. Finally, a case of 2H2E architecture is used to demonstrate the proposed method. The results show that generators in the 2E layout have the highest maintenance priority, which further explains the difference in the importance of each component in PM

Análisis de la situación actual del mantenimiento centrado en la confiabilidad RCM

The objective of this paper is to analyze the current situation of Reliability Centered Maintenance (RCM) in the industry, as well as to show in detail a methodology for its application. To complement this objective, a bibliographic analysis was carried out, for which the main databases containing specialized literature on this subject were consulted, in addition to a logical historical study of the emergence and evolution of this type of maintenance management. The results, expose the theoretical bases and foundations of maintenance management focused on reliability with respect to the current aspects, traditions, and particularities of efficient maintenance management. The procedure for the elaboration of the Failure Modes and Effects Analysis (FMEA) was also detailed, showing that both the RCM procedure and the FMEA methodology are systematic and start from a logical sequence, oriented to prioritize the equipment and reduce the costs of the maintenance activity to the extent that an operational reliability is created. Keywords: Reliability, RCM, Maintenance, Management.El objetivo del presente trabajo consiste en realizar un análisis de la situación actual del mantenimiento centrado en la confiabilidad (RCM) en la industria, así como mostrar en forma detallada una metodología para su aplicación. Para complementar dicho objetivo se realizó un análisis bibliográfico, para lo cual se consultaron las principales bases de datos que contienen literatura especializada sobre esta temática, además se realizó un estudio histórico lógico del surgimiento y evolución de este tipo de gestión de mantenimiento. Los resultados, exponen las bases teóricas y fundamentan la gestión del mantenimiento centrada en la confiabilidad con respecto a los aspectos actuales, tradiciones y particularidades de la gestión eficiente del mantenimiento. Se detalló, además el procedimiento para la elaboración del análisis de modos y efectos de fallas (AMEF), mostrando que tanto el procedimiento RCM como la metodología AMEF son sistemáticos y parten de una secuencia lógica, orientada a priorizar los equipos y reducir los costos de la actividad de mantenimiento en la medida que se crea una confiabilidad operacional. Palabras clave: Confiabilidad, RCM, Mantenimiento, Gestión. Abstract The objective of this paper is to analyze the current situation of Reliability Centered Maintenance (RCM) in the industry, as well as to show in detail a methodology for its application. To complement this objective, a bibliographic analysis was carried out, for which the main databases containing specialized literature on this subject were consulted, in addition to a logical historical study of the emergence and evolution of this type of maintenance management. The results, expose the theoretical bases and foundations of maintenance management focused on reliability with respect to the current aspects, traditions, and particularities of efficient maintenance management. The procedure for the elaboration of the Failure Modes and Effects Analysis (FMEA) was also detailed, showing that both the RCM procedure and the FMEA methodology are systematic and start from a logical sequence, oriented to prioritize the equipment and reduce the costs of the maintenance activity to the extent that an operational reliability is created. Keywords: Reliability, RCM, Maintenance, Management. Información del manuscrito:Fecha de recepción: 03 de mayo de 2021.Fecha de aceptación: 21 de junio de 2021.Fecha de publicación: 09 de julio de 2021

Condition-based maintenance for systems with aging and cumulative damage based on proportional hazards model

This paper develops a condition-based maintenance (CBM) policy for systems subject to aging and cumulative damage. The cumulative damage is modeled by a continuous degradation process. Different from previous studies which assume that the system fails when the degradation level exceeds a specific threshold, this paper argues that the degradation itself does not directly lead to system failure, but increases the failure risk of the system. Proportional hazards model (PHM) is employed to characterize the joint effect of aging and cumulative damage. CBM models are developed for two cases: one assumes that the distribution parameters of the degradation process are known in advance, while the other assumes that the parameters are unknown and need to be estimated during system operation. In the first case, an optimal maintenance policy is obtained by minimizing the long-run cost rate. For the case with unknown parameters, periodic inspection is adopted to monitor the degradation level of the system and update the distribution parameters. A case study of Asphalt Plug Joint in UK bridge system is employed to illustrate the maintenance policy.The work described in this paper was partially supported by a theme-based project grant (T32-101/15-R) of University Grants Council, and a Key Project (71532008) supported by National Natural Science Foundation of China

Optimal maintenance strategy for systems with two failure modes

This paper considers a single-unit system subject to two types of failures: a traditional catastrophic failure and a two-stage delayed failure. Periodic inspections are carried out to identify the defective stage of the two-stage failure process, whereas preventive replacements are implemented to avoid any potential failure due to the catastrophic failure mode. We construct a basic maintenance model and then extend it to the cases of imperfect inspections (i.e., inspections that do not always notice a defective state). We analyze the renewal process of the system and establish the expected long-run cost rate (ELRCR). The optimal inspection period and preventive replacement interval are determined by minimizing the ELRCR. A case study on infusion pumps is presented to illustrate the proposed model

Modelo multiobjetivo para la selección de estrategias óptimas de mantenimiento en sistemas multicomponentes: una aplicación en líneas de transmisión de energía eléctrica

A multi-objective model is proposed for defining optimal maintenance strategies, in systems composed of several interconnected elements. The optimal maintenance strategies derived correspond to a set of efficient actions, focused on maximizing the reliability of the system, and minimizing the associated costs. Optimization is carried out by using evolutionary algorithms type NSGA-II. For the evaluation of the system reliability, a procedure based on Monte Carlo simulation is used, which allows analyzing systems with different performance functions and for component configurations different from the classical ones (series, parallel, k-out-of-N). The proposal is applied to assess electrical power system components, specifically the insulator chains of the transmission lines. Several scenarios illustrate the proposed model. The strategies selected by the model prioritize the most important elements based on costs and/or maintenance. These strategies make up an approximate Pareto front, in which the decision-maker can choose the most suitable strategy according to their interests.En este artículo se formula un modelo multiobjetivo para seleccionar estrategias de mantenimiento óptimas en sistemas formados por varios elementos interconectados. Las aquí planteadas corresponden al conjunto de acciones eficientes, centradas en maximizar la confiabilidad del sistema y, a su vez, minimizar los costos asociados. La optimización se realiza mediante el uso de algoritmos evolutivos tipo NSGA-II. Para evaluar la confiabilidad del sistema se utiliza un procedimiento basado en simulación de Monte Carlo, que permite analizar sistemas con distintas funciones de desempeño y para configuraciones de componentes diferentes a las clásicas (serie, paralelo, k-out-of-N). La propuesta se analiza para los componentes de un sistema eléctrico de potencia, específicamente las cadenas de aisladores de las líneas de transmisión, y varios escenarios de cálculo. Las estrategias seleccionadas por el modelo priorizan los elementos más importantes, según costo o mantenimiento, y conforman un frente de Pareto aproximado donde el decisor puede seleccionar la más adecuada, de acuerdo con sus intereses

Gestión del mantenimiento preventivo de los equipos de enfriamiento de moldes para mejorar la productividad en la planta de inyección de una empresa de fabricación de productos plásticos, Ate, 2019

En la investigación titulada “Gestión del mantenimiento preventivo de los equipos de enfriamiento de moldes para mejorar la productividad en la planta de inyección de una empresa de fabricación de productos plásticos, Ate, 2019” tiene el objetivo general Determinar de qué manera la Gestión del mantenimiento preventivo de los equipos de enfriamiento de moldes mejora la Productividad de la planta de inyección de una empresa de fabricación de producto plástico, Ate, 2019. La metodología de investigación es de enfoque cuantitativo, de tipo aplicada y diseño cuasi experimental. La población fueron los datos numéricos de las variables bajo estudio, gestión del mantenimiento preventivo y productividad de la empresa Fabricación de productos plásticos. La muestra determinada fueron los datos numéricos de los últimos 12 meses, desde mayo a octubre del año 2018 (pre) y de noviembre del año 2018 a abril del año 2019 (post). referidos a la gestión del mantenimiento preventivo y productividad. La técnica empleada fue la observación y el instrumento fue la ficha de observación. La validación de los instrumentos se realizó a través del juicio de expertos. Para realizar el análisis de los datos se utilizó el programa estadístico SPSS Versión 24 con el cual se buscó representar los datos cuantitativos, a través de la estadística descriptiva y la estadística inferencial, para la interpretación de los resultados. Finalmente, se concluye que la Gestión del mantenimiento preventivo de los equipos de enfriamiento de moldes sí logra mejorar la productividad en 5.1%, la eficiencia 5.6% y la eficacia en 11%