• Title, Summary, Keyword: Maintenance

Search Result 14,633, Processing Time 0.072 seconds

A Study on Proper Maintenance Level Selection of Track Ballast Structures Using LCC Analysis (LCC분석을 통한 궤도도상구조의 적정 유지관리수준 선정에 관한 연구)

  • An, Kook;Lee, Ho-Yeol;Chu, Jang-Sik;Park, Mi-Yun;Lim, Jong-Kwon
    • Proceedings of the KSR Conference
    • /
    • /
    • pp.232-237
    • /
    • 2008
  • Several research institutes including KISTEC and KRRI etc., recently, have studied maintenance activities and performance, in order to determine proper maintenance level and maintenance cost of rail tracks. But it may extremely difficult to make a decision in maintenance matters of concrete track and ballast containing other sub-components. For these reasons, this study investigate variables related to current maintenance, essential maintenance, and preventive maintenance. It is intended to suggest estimation method of proper maintenance cost maximizing rail track performance. It is stated that proposed approach may be very useful to make a decision of proper maintenance level. Typical section of rail track is applied for calculation of life cycle cost according to each maintenance strategy. A proper profile for maintenance is determined minimum life cycle

  • PDF

Developing a Decision-Making Model to Determine the Preventive Maintenance Schedule for the Leased Equipment (대여 장비의 예방정비 일정 결정을 위한 의사 결정 모델 개발)

  • Lee, Ju-hyun;Bae, Ki-ho;Ahn, Sun-eung
    • Journal of the Society of Korea Industrial and Systems Engineering
    • /
    • v.41 no.2
    • /
    • pp.24-31
    • /
    • 2018
  • As a system complexity increases and technology innovation progresses rapidly, leasing the equipment is considered as an important issue in many engineering areas. In practice, many engineering fields lease the equipment because it is an economical way to lease the equipment rather than to own the equipment. In addition, as the maintenance actions for the equipment are costly and need a specialist, the lessor is responsible for the maintenance actions in most leased contract. Hence, the lessor should establish the optimal maintenance strategy to minimize the maintenance cost. This paper proposes two periodic preventive maintenance policies for the leased equipment. The preventive maintenance action of policy 1 is performed with a periodic interval, in which their intervals are the same until the end of lease period. The other policy is to determine the periodic preventive maintenance interval minimizing total maintenance cost during the lease period. In addition, this paper presents two decision-making models to determine the preventive maintenance strategy for leased equipment based on the lessor's preference between the maintenance cost and the reliability at the end of lease period. The structural properties of the proposed decision-making model are investigated and algorithms to search the optimal maintenance policy that are satisfied by the lessor are provided. A numerical example is provided to illustrate the proposed model. The results show that a maintenance policy minimizing the maintenance cost is selected as a reasonable decision as the lease term becomes shorter. Moreover, the frequent preventive maintenance actions are performed when the minimal repair cost is higher than the preventive maintenance cost, resulting in higher maintenance cost.

The Current Issues on Warranty & Maintenance Policy of the Second-Hand Products (중고제품의 보증과 보전정책에 대한 최근 연구 동향)

  • Lim, Jae-Hak
    • Journal of Applied Reliability
    • /
    • v.17 no.2
    • /
    • pp.159-167
    • /
    • 2017
  • Purpose: The purpose of this research is to study research trend in the field of warranty and maintenance policy of second-hand products. Methods: To this end, we consider research articles, which deal with warranty and maintenance of the second-hand products, published on journals during the past 20 years and classify them by taxonomy scheme proposed by Shafiee and Chukova (2013). The taxonomy scheme consists of three maintenance models in warranty for second-hand product. In each models, we analyze proposed maintenance and warranty policies with respect to types of upgrade models, types of preventive maintenances, decision variables and decision criteria model. Results: We obtain the scheme of maintenance and warranty of the second-hand products and define cost related to warranty and maintenance of the second-hand item. Also, we summarize the characteristics of maintenance and warranty policies in each classified model. Conclusion: There have been several research reviews on maintenance and warranty polity of new products. This research surveys researches of authors during the past 20 years and classifies, summarizes and compares proposed maintenance and warranty policies of the second-hand products. This research provides useful information to researchers who are interested in maintenance and warranty of the second-hand products.

Numerical Experiments for the Stress-Reducing Preventive Maintenance Model (수치실험을 통한 스트레스 감소 예방보수모형의 고찰)

  • Park, Jong Hun
    • Journal of the Society of Korea Industrial and Systems Engineering
    • /
    • v.43 no.3
    • /
    • pp.41-52
    • /
    • 2020
  • This paper investigates the stress-reducing preventive maintenance model through numerical experiments. The preventive maintenance model is used to analyze the relationship between related conditions and variables to gain insight into the efficient operation of the system when performing preventive maintenance in real-world situations. Various preventive maintenance models have been developed over the past decades and their complexity has increased in recent years. Increasing complexity is essential to reflect reality, but recent models can only be interpreted through numerical experiments. The stress-reducing preventive maintenance is a newly introduced preventive maintenance concept and can only be interpreted numerically due to its complexity, and has received little attention because the concept is unfamiliar. Therefore, for information purposes, this paper investigates the characteristics of the stress-reducing preventive maintenance and the relationship between parameters and variables through numerical experiments. In particular, this paper is focusing on the economic feasibility of stress-reducing preventive maintenance by observing changes in the optimal preventive maintenance period in response to changes in environmental stress and the improvement factor. As a result, when either the environmental stress or the improve effect of stress-reducing preventive maintenance is low, it is not necessary to carry out the stress-reducing preventive maintenance at excessive cost. In addition, it was found that the age reduction model is more economical than the failure rate reduction model.

A Study on the Decision of an Optimal Maintenance Period for Ship's Machinery Items using the Cumulative Hazard Rate Function for Weibull Distribution (Weibull형 고장분포를 갖는 선박용 부품의 최적 보전시기의 결정수법에 관한 연구)

  • 유희한
    • Journal of Advanced Marine Engineering and Technology
    • /
    • v.24 no.2
    • /
    • pp.90-96
    • /
    • 2000
  • The technology of preventive maintenance and corrective maintenance is widely applied to ships in order to maintain the good voyageable condition. One of the most important fields of marine engineering is to seek the maximum availability and to solve the stochastic maintenance problem such that the cost for corrective maintenance is minimized. Accordingly, for the purpose of making the most suitable maintenance schedule which minimizes the expected cost function, this paper suggests the method to grasp the failure characteristics by the ship's maintenance data that are collected from the past. And, suggests the method to estimate the optimal maintenance interval by using the dynamic programming and the cumulative hazard rate function attained from the maintenance data.

  • PDF

A Comparative Study on Optimal Generation Maintenance Scheduling with Marginal Maintenance Cost and Levelized Risk Methods (한계보수비용법 및 위험지수 평준화법에 의한 최적전원보수계획의 비교)

  • 이봉용;심건보
    • The Transactions of the Korean Institute of Electrical Engineers
    • /
    • v.41 no.1
    • /
    • pp.9-17
    • /
    • 1992
  • Proper resource allocation is also a very important topic in power system problems, especially in operation and planning. One such is optimal maintenance problem in operation and planning. Least cost and highest reliability should be the subjects to be pursued. A probabilistic operation simulation model developed recently by authors is applied to the proboem of optimal maintenance scheduling. Three different methods are compared, marginal maintenance cost, levelized risk and maintenance space. The method by the marginal maintenance costs shows the least cost, the highest reliability and the highest maintenance outage rates. This latter characteristics may considerably influence the results of genetation planning, because the usual maintenance outages obtained from the other methods have shown to be lower.

  • PDF

Not Preventive Maintenance, But Predictive Maintenance (예방(예지) 정비의 필요성)

  • Jeon, Hyeong-Sik;White, Glenn
    • Journal of KSNVE
    • /
    • v.4 no.4
    • /
    • pp.459-467
    • /
    • 1994
  • Various maintenance programs and techniques have been implemented for roating machineries, since machines were invented for commerical use. The earliest type of maintenance was run-to-failure, where the machine was run until a fault caused to fail in service. It was obviously an expensive approach due to the unpredictability of the machine condition. Another type is the periodic maintenance, where machines are disassembled and overhauled on regular schedules. With the advent of reliable data collectors including FFT analyzer and developing of versatile supporting software such as ExpertALERT system, the predictive maintenance is known to be the most feasible maintenance type these days. The vibration analysis enables for a maintenance crew to find the exact cause of fault on a machine and to make a proper maintenance schedule with a trend analysis. The predicitive maintenance is considered to be the most important part of pro-active maintenance.

  • PDF

Preventive Maintenance Plan of Power System Unit Considering Imperfect Maintenance (불안전한 유지보수를 고려한 전력 설비의 예방 정비 계획)

  • Byeon, Yoong-Tae;Kim, Hyung-Jun;Kim, Jin-O;Kim, Hyung-Chul
    • Proceedings of the KIEE Conference
    • /
    • /
    • pp.328-330
    • /
    • 2007
  • Recently, the research of PM (Preventive Maintenance) method on the RCM(Reliability-Centered Maintenance) of the system equipment is being actively advanced for a few years. The state of the power equipment is maintained like the states of the between 'as good as new ones' and 'as bad as old ones' by imperfect Maintenance that implies the life decrease of the equipment by frequent breakdown, the error of maintenance process, and so on. So, the Maintenance method considering the real case has to reflect Imperfect maintenance than perfect maintenance. This paper suggests the Preventive Maintenance method by using Quasi - Renewal Theory for the gas turbine equipment as deliberating the imperfect maintenance for the real cases.

  • PDF

A Study on Evaluation of corrective maintenance for the ATP on-board equipped in Tilting train (틸팅열차 차상신호장치 교정유지보수 평가에 관한 연구)

  • Lee, Kang-Mi;Shin, Duc-Ko;Baek, Jong-Hyen;Lee, Jae-Ho
    • Proceedings of the KSR Conference
    • /
    • /
    • pp.1989-1992
    • /
    • 2009
  • Maintenance is classified preventive maintenance before performing equipment failure and corrective maintenance after performing equipment failure. In preventive maintenance, we may analyze the failure data to end from beginning of equipment and allocate maintenance method and calculate maintenance cycle quantitatively by the failure data analysis. So, it has a merit to reduce system maintenance cost and to operate effectively but, it require high cost in system introducing and continuous operation to end of system. In corrective maintenance, we may calculate MTTR(mean time to repair) quantitatively based on function failure time. it can be based on establishing maintenance system for operation efficiency. In this paper, we may reflect the MTTR for the onboard equipped in Tilting train to establish maintenance system for Tilting train operation efficiency.

  • PDF

Scheduling of Preventive Maintenance for Generating Unit Considering Condition of System (시스템의 상태를 고려한 발전설비의 예방 유지보수 계획 수립)

  • Shin, Jun-Seok;Byeon, Yoong-Tae;Kim, Jin-O;Kim, Hyung-Chul
    • The Transactions of The Korean Institute of Electrical Engineers
    • /
    • v.57 no.8
    • /
    • pp.1305-1310
    • /
    • 2008
  • Traditional maintenance planning is based on a constant maintenance interval for equipment life. In order to consider economic aspect for time based preventive maintenance, preventive maintenance is desirable to be scheduled by RCM(Reliability-Centered Maintenance) evaluation. The main objective of RCM is to reduce the maintenance cost, by focusing on the most important functions of the system and avoiding or removing maintenance actions that are not strictly necessary. So, Markov state model is utilized considering stochastic state in RCM. In this paper, a Markov state model which can be used for scheduling and optimization of maintenance is presented. The deterioration process of system condition is modeled by the stepwise Markov model in detail. Also, because the system is not continuously monitored, the inspection is considered. In case study, simulation results about RCM will be shown using the real historical data of combustion turbine generating unit in Korean power systems.