Probabilistic indicators of imperfect inspections used in modeling condition-based and predictive maintenance

Raza, Ahmed; Ulansky, Vladimir

doi:10.1177/1748006x221136317

Cited by 3 publications

(2 citation statements)

References 26 publications

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“…The maintenance effectiveness indicator was the expected cost per regeneration cycle. Studies [53,54] have shown that the probabilities of imperfect inspections at condition-based and predictive maintenance are functions of the degradation model parameters and strongly depend on time. In the study [55], the case of imperfect testing of the crack depth in a fighter wing was considered.…”

Section: Literature Reviewmentioning

confidence: 99%

Classification of Systems and Maintenance Models

Ulansky

Raza

2023

Aerospace

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Maintenance is an essential part of long-term overall equipment effectiveness. Therefore, it is essential to evaluate maintenance policies’ effectiveness in addition to planning them. This study provides a classification of technical systems for selecting maintenance effectiveness indicators and a classification of maintenance models for calculating these indicators. We classified the systems according to signs, such as system maintainability, failure consequences, economic assessment of the failure consequences, and temporary mode of system use. The classification of systems makes it possible to identify 13 subgroups of systems with different indicators of maintenance effectiveness, such as achieved availability, inherent availability, and average maintenance costs per unit of time. When classifying maintenance models, we used signs such as the system structure in terms of reliability, type of inspection, degree of unit restoration, and external manifestations of failure. We identified one hundred and sixty-eight subgroups of maintenance models that differed in their values for specified signs. To illustrate the proposed classification of maintenance models, we derived mathematical equations to calculate all considered effectiveness indicators for one subgroup of models related to condition-based maintenance. Mathematical models have been developed for the case of arbitrary time-to-failure law and imperfect inspection. We show that the use of condition-based maintenance significantly increases availability and reduces the number of inspections by more than half compared with corrective maintenance.

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Section: Literature Reviewmentioning

confidence: 99%

Classification of Systems and Maintenance Models

Ulansky

Raza

2023

Aerospace

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“…The expected losses are determined using the mathematical expectation formula for a continuous variable, which is the failure time. Ulansky and Raza (2023) have developed formulas to calculate unconditional and conditional probabilities of correct and incorrect decisions during a single inspection. The numerical example highlights that these probabilities are significantly influenced by the timing of inspections and the moment of failure.…”

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confidence: 99%

Model of condition-based maintenance with multiple imperfect inspections

Raza,

Ulansky

2023

Proc. Of the 12th IMA International Conference on Modelling in Industrial Maintenance and Reliability

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Condition-based maintenance (CBM) refers to proactive maintenance carried out based on the system's condition. In this study, we developed mathematical equations to calculate maintenance effectiveness indicators, as achieved availability, availability, mission availability, average maintenance costs per unit of time, and operational probability of failure-free operation. We considered a with a single-component structure, where the type of imperfect inspection corresponds to CBM, the perfect repair is employed, and only wear-out failures occur in the system. Mathematical models have been derived for cases involving multiple imperfect inspections and an arbitrary time-to-failure law. We determined the optimal number of inspections by the criterion of maximum achieved availability for a specific stochastic degradation process, considering both condition-based and corrective maintenance. Our research demonstrates that significantly improves achieved availability and reduces the required inspections.and Results

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Delay time model for determining the effectiveness of a system under adverse conditions of production and inspection

Cavalcante,

Santos,

Paiva

et al. 2023

Proceedings of the Institution of Mechanical Engineers, Part O:

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The effectiveness of production is influenced by different events that may disrupt the original production plan, such as degradation in the production process, additional demands and inspection errors. To analyze the impact of these issues on production planning, we propose a delay time model for a single-component system that can experience four different states: good, minor defective, major defective and failed. The model uses cost-rate as a measure of production effectiveness. We conducted an investigation into the consequences of the degradation process, specifically focusing on its impact on the generation of nonconforming products. Additionally, we examined the effects of additional demands on the rate of rework products and analyzed the impact of inspection errors, including both the induction and non-detection of defects. These issues represent adverse conditions that many production systems run into their operation and maintenance processes. The results of our study advise the best strategies to deal with these adverse conditions in order to minimize their impacts on effectiveness of a production system. The proposed model serves as a guide and illustrative example of how these issues can be incorporated in the process of optimizing the effectiveness of production. From this perspective, this paper’s main contribution is a series of insights that widens the manager’s view about the production process in a real system, in which perfect and suitable conditions are not commonly present.

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Probabilistic indicators of imperfect inspections used in modeling condition-based and predictive maintenance

Cited by 3 publications

References 26 publications

Classification of Systems and Maintenance Models

Classification of Systems and Maintenance Models

Model of condition-based maintenance with multiple imperfect inspections

Delay time model for determining the effectiveness of a system under adverse conditions of production and inspection

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