• Title, Summary, Keyword: Maintainability

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The Improvement of maintainability evaluation method at system level using system component information and fuzzy technique (시스템의 구성품 정보와 퍼지 기법을 활용한 시스템 수준 정비도 평가 방법의 개선)

  • Yoo, Yeon-Yong;Lee, Jae-Chon
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.3
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    • pp.100-109
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    • 2019
  • Maintainability indicates the extent to which maintenance can be done easily and quickly. The consideration of maintainability is crucial to reduce the operation and support costs of weapon systems, but if the maintainability is evaluated after the prototype production is done and necessitates design changes, it may increase the cost and delay the schedule. The evaluation should verify whether maintenance work can be performed, and support the designers in developing a design to improve maintainability. In previous studies, the maintainability index was calculated using the graph theory at the early design phase, but evaluation accuracy appeared to be limited. Analyzing the methods of evaluating the maintainability using fuzzy logic and 3D modeling indicate that the design of a system with good maintainability should be done in an integrated manner during the whole system life cycle. This paper proposes a method to evaluate maintainability using SysML-based modeling and simulation technique and fuzzy logic. The physical design structure with maintainability attributes was modeled using SysML 'bdd' diagram, and the maintainability was represented by an AHP matrix for maintainability attributes. We then calculated the maintainability using AHP-based weighting calculation and fuzzy logic through the use of SysML 'par' diagram that incorporated MATLAB. The proposed maintainability model can be managed efficiently and consistently, and the state of system design and maintainability can be analyzed quantitatively, thereby improving design by early identifying the items with low maintainability.

Guide-line for Developing a Maintainability Program (보전성 경영 프로그램 개발을 위한 지침)

  • 이낙영;김종걸;권영일;홍연웅;전영록;나명환
    • Proceedings of the Korean Reliability Society Conference
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    • pp.269-269
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    • 2001
  • Maintainability refers to the ease with which maintenance work can be done. It involves the process of ensuring that products can be easily and safely maintained and that the maintenance support requirement is minimized. When a product has a reasonably long life, the cost of operation and support during that life can greatly exceed the initial capital cost. The value to the customer of optimizing maintainability should be evident. Some effort and expense applied to achieving a product which can be easily and cheaply maintained will make very significant savings in the life cycle costs. In this paper, the International Standard IEC 60300-3-10, which is the application guide for maintainability, is considered. This standard can be used to implement a maintainability program covering the initiation, development and in-service phases of a product. It provides guidance on how the maintenance aspects of the tasks should be considered in order to achieve optimum maintainability. The elements of a maintainability program, which are maintenance policy and concept, maintainability studies, project management, design for maintainability, analysis and prediction methods, maintenance verification and validation, analysis of life cycle cost, maintenance support planning, and collection and analysis of maintenance data, are fully discussed in this paper.

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Application Guide of Reliability Maintainability and Availability (신뢰성, 보전성 및 가용성 적용 모델)

  • Choi, Sung-Woon
    • Proceedings of the Safety Management and Science Conference
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    • pp.309-322
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    • 2007
  • This paper shows application guide of dependability data from the field, life cycle costing, and maintainability. Moreover, this study introduces mathematical expressions and predictions for reliability, availability and maintainability. This paper also shows compliance test procedures for steady-state availability, and application of Markov techniques.

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Computation of Maintainability Index Using SysML-Based M&S Technique for Improved Weapon Systems Development (SysML 기반 모델링 및 시뮬레이션 기법을 활용한 무기체계 정비도 지수 산출)

  • Yoo, Yeon-Yong;Lee, Jae-Chon
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.11
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    • pp.88-95
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    • 2018
  • Maintainability indicates how easily a system can be restored to the normal state when a system failure occurs. Systems developed to have high maintainability can be competitive due to reduced maintenance time, workforce and resources. Quantification of the maintainability is possible in many ways, but only after prototype production or with historical data. As such, the graph theory and 3D model data have been used, but there are limitations in management efficiency and early use. To solve this problem, we studied the maintainability index of weapon systems using SysML-based modeling and simulation technique. A SysML structure diagram was generated to simultaneously model the system design and maintainability of system components by reflecting the maintainability attributes acquired from the system engineering tool. Then, a SysML parametric diagram was created to quantify the maintainability through simulation linked with MATLAB. As a result, an integrated model to account for system design and maintainability simultaneously has been presented. The model can be used from early design stages to identify components with low maintainability index. The design of such components can be changed to improve maintainability and thus to reduce the risks of cost overruns and time delays due to belated design changes.

A Study on the Reliability and Maintainability Analysis Process for Aircraft Hydraulic System (항공기용 유압 시스템 신뢰도 및 정비도 분석 프로세스 고찰)

  • Han, ChangHwan;Kim, KeunBae
    • Journal of the Korea Society of Systems Engineering
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    • v.12 no.1
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    • pp.105-112
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    • 2016
  • An aircraft must be designed to minimize system failure rate for obtaining the aircraft safety, because the aircraft system failure causes a fatal accident. The safety of the aircraft system can be predicted by analyzing availability, reliability, and maintainability of the system. In this study, the reliability and the maintainability of the hydraulic system are analysed except the availability, and therefore the reliability and the maintainability analysis process and the results are presented for a helicopter hydraulic system. For prediction of the system reliability, the failure rate model presented in MIL-HDBK-217F is used, and MTBF is calculated by using the Part Stress Analysis Prediction and quality/temperature/environmental factors described in NPRD-95 and MIL-HDBK-338B. The maintainability is predicted by FMECA(Failure Mode, Effect & Criticality Analysis) based on MIL-STD-1629A.

Validation of Availability, Maintainability and Safety for Subway Elevating Equipment (도시철도 승강설비의 가용성, 유지보수성 및 안전성 입증)

  • Lee, Hwan-Deok;Jung, Won
    • Journal of Applied Reliability
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    • v.16 no.4
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    • pp.272-279
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    • 2016
  • Purpose: In order to fulfill the RAMS (Reliability Availability Maintainability and Safety) requirements in Korean railway systems, specific target metrics should be measured and met the requirements when ordering a new system. This paper presents a procedure to predict and demonstrate the availability, maintainability and safety of subway elevators, escalators and PSD (platform screen doors) systems. Methods: The system manufacturer predicts availability and maintainability with lab and field tested data. After installation, availability and maintainability are demonstrated based on the actual operational data. The data was collected from the FRACAS (Failure Report and Corrective Action System). Results: Methods and process of assessing and analyzing the availability, maintainability and safety are presented for elevating services and PSD systems. The data obtained through the actual operation of the equipment is analyzed and maintained to predict the RAMS based on the component and system level failure data acquired. Conclusion: This study presented an application using IEC 62278 and operational data which can be used in the design and development stage to achieve the RAMS target value of the subway elevators, escalators and PSD systems.

A Study on the Maintainability Prediction and Demonstration (열차제어시스템 유지보수도예측 및 입증에 관한 연구)

  • Shin, Duc-Ko;Lee, Jae-Ho
    • Proceedings of the KIEE Conference
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    • pp.56-58
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    • 2005
  • This paper for the Train control system which has been used in the railway system for the purpose of headway control is regarded as safety-critical system, which is based on embedded controller. Therefore, for the maintainability, the maintenance time shall be predicted correctly in order to improve availability of railway system and the predictive values shall be proved through the test. In conclusion, for the maintainability of train control system, the solution for exact prediction based on related international standard and the system for justification of derived predictive values shall be proposed.

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Availability Measures for Repairable Dynamic Reliability Models (수리 가능한 동적 신뢰도 모델의 가용도 척도)

  • Choi, Sung-Woon
    • Journal of the Korea Safety Management and Science
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    • v.8 no.5
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    • pp.253-264
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    • 2006
  • This paper is to derive three reliability and eight maintainability measures after organizing total time. I propose inherent availability,.achieved availability and operational availability with the new and useful reliability and maintainability measures above. Especially, inherent availability measure extends the repairable system reliability models.

Allocation of the Optimal Reliability and Maintainability in Manufacturing Systems (제조 시스템의 최적 신뢰도 및 보전도 할당)

  • 이상철
    • Journal of the Society of Korea Industrial and Systems Engineering
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    • v.22 no.50
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    • pp.23-32
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    • 1999
  • Reliability and maintainability allocation in the analysis of the system's design, with the objective of planning and installing the individual components in such a way that the system performance is achieved. This paper has been made to solve an important task in reliability management of manufacturing systems within the general objective being to increase productivity while maintaining costs low. Thus, the purpose of this paper is to provide an analytical approach to determine an optimal reliability and maintainability allocation, trading off among system performance and parts investment costs. Two important considerations will be addressed in this regard : (ⅰ) determine the reliability and maintainability allocation of parts which maximizes a given production index, having fixed the total cost of investments ; and (ⅱ) determine the reliability and maintainability allocation which minimizes the total cost of investments, having fixed a minimum acceptable level of productivity. The procedure proposed in this paper is able to provide to managers and designers useful indications on the reliability and maintainability characteristics of parts in series -parallel systems. And this heuristic model is a decision support tool for contractors who are involved in large scale design projects such as ship and aircraft design. Numerical examples prove that an approximate expression of the average throughput rate is sufficiently accurate to be used in a numerical optimization method.

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A Study on the Maintainability Prediction in the Initial Design Phase between Weapon System Development (무기체계 개발간 초기 설계단계에서의 정비도 예측방안 연구)

  • Kim, Yeoungseok;Hur, Jangwok
    • Journal of the Korea Institute of Military Science and Technology
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    • v.22 no.6
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    • pp.824-831
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    • 2019
  • For effective development in consideration of the maintainability of the weapon system, it is necessary to understand whether the maintainability design requirements are satisfied at the early phase of development. This requires the application of an early design phase maintainability prediction process to provide opportunities for improvement. By defining the ambiguity group definition, fault isolation level, fault isolation probability, and countermeasures for faults, it was possible to predict early phase development. The MTTR of the initial design phase applying Procedure V to the artillery system was 3.46H, which is about 16 % higher than 2.98H, the MTTR using Procedure II. This is a result of system design ambiguity that has not been specified in the early phase of development.