• Title/Summary/Keyword: replacement cycle

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A Study on Reliability Analysis & Determination of Replacement Cycle of the Railway Vehicle Contactor (철도차량 접촉기의 신뢰성 분석 및 교환주기 결정에 대한 연구)

  • Park, Minheung;Rhee, Sehun
    • Journal of Applied Reliability
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    • v.17 no.4
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    • pp.316-324
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    • 2017
  • Purpose: The purpose of this study is to determine the replacement cycle applied age replacement policy by reliability analysis based on railway vehicle contactor's failure history data. Method: We performed reliability analysis based on railway vehicle contactor's failure history data. We found a suitable distribution by goodness of fit test and predicted the reliability through estimation of scale & shape parameter. Considering cost information we determined the replacement cycle that minimize the opportunity cost. Result: Suitable distribution was the Weibull and scale parameter & shape parameter are estimated by reliability analysis. The replacement cycle was predicted and MTTF, $B_6$ percentile life were suggested additionally. Conclusion: We confirmed that failure rate type of railway vehicle contactor is degradation model having a time dependent characteristic and examined the replacement cycle in our country's operating environment. We expect that this study result contribute to railway operation agency for maintenance policy decision.

A study on estimation status and improvement plan of the repair and replacement cycle of a building (건축물 수선교체주기 산정현황과 개선방안에 관한 연구)

  • Kim, Jong-Rok;Son, Jae-Ho
    • Journal of the Korea Institute of Building Construction
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    • v.10 no.1
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    • pp.193-198
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    • 2010
  • This study aimed at presenting the improvement plan for estimation of the repair and replacement cycle to analyze these current problems by considering the repair and replacement cycle theoretically and examining estimation status of home and abroad, and then drawing implication and problem based on brainstorming and expert opinion. The findings of a study is as follows. First, the problem is, for the domestic, that there is no clear standard of division to the cycle of repair and replacement and the repair and replacement cycle considering capability to deal with the change by construction method, development of the function of material and the number of years of progress is not being applied. That is, an estimation of economical repair and replacement cycle which considers the case that a large scale repair with the level of remodeling is done between 25 years and 35 years is necessary. For estimating the repair and replacement cycle, foreign country is providing this according to the use or the level of function of a building, but it is not the case for the domestic. A characteristic of each building should be reflected and the standard of estimation of the repair and replacement cycle to new construction material or method should be prepared to improve this. In addition, the method of classification of the subject item for the repair and replacement is necessary to be reorganized to be able to apply the standard of initial construction item of a building. Also, it is considered that a service standard which can reset the repair and replacement cycle based on status of a building with escape from the existing definite setup of the repair and replacement cycle through the management of background data of the repair and replacement is going to be necessary.

Optimal Periodic Replacement Policy Under Discrete Time Frame (이산 시간을 고려한 시스템의 교체와 수리 비용 최적화 연구)

  • Lee, Jinpyo
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.43 no.1
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    • pp.61-69
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    • 2020
  • Systems such as database and socal network systems have been broadly used, and their unexpected failure, with great losses and sometimes a social confusion, has received attention in recent years. Therefore, it is an important issue to find optimal maintenance plans for such kind of systems from the points of system reliability and maintaining cost. However, it is difficult to maintain a system during its working cycle, since stopping works might incur users some troubles. From the above viewpoint, this paper discusses minimal repair maintenance policy with periodic replacement, while considering the random working cycles. The random working cycle and periodic replacement policies with minimal repair has been discussed in traditional literatures by usually analyzing cases for the nonstopping works. However, maintenance can be more conveniently done at discrete time and even during the working cycle in real applications. So, we propose that periodic replacement is planned at discrete times while considering the random working cycle, and moreover provide a model in which system, with a minimal repair at failures between replacements, is replaced at the minimum of discrete times KT and random cycles Y. The average cost rate model is used to determine the optimal number of periodic replacement.

A Study on the Determination of Replacement Time for Military Vehicle Using Availability Analysis ­ Focused on 2 \frac{1}{2} Ton Cargo­ (군용 기동장비의 가용도 분석을 통한 교체시기 결정에 관한 연구 ­2 \frac{1}{2} 톤 차량을 중심으로­)

  • 하형호;강성진
    • Journal of the military operations research society of Korea
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    • v.29 no.2
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    • pp.81-99
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    • 2003
  • This paper propose a method determining life cycle for military vehicle using availability analysis. Many studies determining life cycle for military equipments have been done recently However, those studies focused on economic life such as average system cost method, equivalent annual cost method and cumulative operations cost method. In many case, those results are not appropriate in deciding replacement in the field situation, we consider an effective life cycle method using availability concept. In order to determine an equipment life cycle. Two kinds of availability is considered. One is equipment yearly availability, the other is operational availability with operating distance per year. The life cycle is determined by achieving unit target availability level. The result using this concept for K­511 military vehicle life cycle is about 19 years, which is longer than previous studies.

Optimal Working Cycles for Minimal Repair Policy (정기교체 및 최소수리를 고려한 작업주기 횟수 최적화)

  • Lee, Jinpyo
    • Journal of Korean Society for Quality Management
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    • v.48 no.1
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    • pp.201-214
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    • 2020
  • Purpose: The purpose of this paper is to determine an optimal number of cycle times for the replacement under the circumstance where the system is replaced at the periodic time and the multiple number of working cycles whichever occurs first and the system is minimally repaired between the replacements if it fails. Methods: The system is replaced at periodic time () or cycle time, whichever occurs first, and is repaired minimally when it fails between successive replacements. To determine the optimal number of cycle times, the expected total cost rate is optimized with respect to the number of cycle times, where the expected total cost rate is defined as the ratio of the expected total cost between replacements to the expected time between replacements. Results: In this paper, we conduct a sensitivity analysis to find the following results. First, when the expected number of failures per unit time increases, the optimal number of cycle times decreases. Second, when the periodic time for replacement becomes longer, the optimal number of cycle times decreases. Third, when the expected value for exponential distribution of the cycle time increases, the optimal number of cycle times increases. Conclusion: A mathematical model is suggested to find the optimal number of cycle times and numerical examples are provided through the sensitivity analysis on the model parameters to see the patterns for changes of the optimal number of cycle times.

A study on reliability analysis model of the repair and replacement cycle of a building which utilizes Monte Carlo Simulation (몬테카를로 시뮬레이션을 활용한 건축물 수선교체주기 신뢰성 분석 모델에 관한 연구)

  • Kim, Jong-Rok;Jung, Young-Han;Son, Jae-Ho
    • Journal of the Korea Institute of Building Construction
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    • v.10 no.2
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    • pp.41-50
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    • 2010
  • This study presented a model that can enable a reliability analysis for the repair and replacement cycle of a building by using background repair and replacement data and expert opinion as foundation data and applying Monte Carlo Simulation. The presented model offers the time of the repair and replacement of building elements for the period of a year, and supports the prediction of repair and replacement and expenses demand in advance while planning the maintenance of a building. In addition, the model will significantly reduce the risks to the building owner with regard to maintenance decisions. In addition, when a person in charge of the maintenance of large-scale building assets is having difficulties making decisions regarding the repair and replacement of existing building elements due to a lack of background data to support a long-term policy on the repair and replacement requirements, an engineering solution that can ensure the adequacy of this is provided. In summary, it can be largely divided into three study results. First, a method of estimating the repair and replacement cycle that can deal with the development of a construction system was developed. Second, a probabilistic methodology that can quantify the risk of the repair and replacement cycle was proposed. Third, the proposed model can be used as a means of supporting designer and constructor in making decisions for the life cycle plan of a building during a construction project.

Analysis of Replacement Cycle by Eyeglasses Scratches in Daily Life (일상생활 속 안경렌즈 흠집에 의한 교체주기 분석)

  • Jung, Mi-A;Lee, Eun-Hee
    • Journal of the Korea Convergence Society
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    • v.10 no.12
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    • pp.447-451
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    • 2019
  • This study were to investigate the scratches and replacement cycles of eyeglasses according to personal characteristics in daily life. The subjects were 58 people who voluntarily participated in this study. The replacement cycle of eyeglasses according to the contact of eyelashes with eyeglasses, type and the number of eyeglasses wiped on a day were analyzed. The statistical analysis were performed by X2 test and Fisher's exact test. The average replacement cycle of the eyeglasses were longer females than males. The eyeglasses replacement cycle were significantly shorter when the eyelashes contacted the eyeglasses and when the eyeglasses were wiped using a tissue or clothes other than the eyeglasses towel. The coating film of the eyeglasses may be damaged by the convergence effect such as eyelashes or minor carelessness in daily life, and this study will continue to follow up on this result.

Extension Feasibility on Replacement Cycle of Rotor Blade Equipped for Low Pressure First Stage in a 150 MW Gas Turbine (150 MW급 가스터빈 저압 1단 회전익 교체주기 연장 가능성 연구)

  • Lim, Jong-Ho;Lee, Jae-Heon
    • Plant Journal
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    • v.9 no.4
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    • pp.31-36
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    • 2013
  • In order to extend a hot gas parts replacement cycle of a gas turbine, blade row 1 from low pressure turbine, which has a significant impact on the cycle, has been selected from stored set after one cycle use. Taking into account the status of the first stage moving blade in LP turbine operated more than 27,000 equivalent operating hours(EOH) and the replacement cycle in the same type of gas turbine, the replacement of the high temperature components installed on the GT, a study subject, can be extended from 24,000 to 27,000 EOH.

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Estimating Retirement Consumption Needs Using Target Replacement Rate (목표 소득대체율을 통한 은퇴소비의 추정)

  • 여윤경
    • Journal of the Korean Home Economics Association
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    • v.40 no.3
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    • pp.83-97
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    • 2002
  • This study estimates the consumption needs of preretired households through target replacement ratio approach. Based on the Life Cycle Model, this study used the household expenditure function to derive the target replacement ratio appropriate for each household. The target replacement ratio is estimated using the 1996 National Survey of family Income and Expenditure by National Statistical Office. The estimated target replacement ratio was 82.4% for married couple households, and 85.1% for single households. Total retirement consumption needs during entire retirement period was 161,620,000 won for married couple households, and 50,532,039 won for single households.

A Study on the BIM Application for Establishment of the Repair and Replacement Cycle of Long-Life Housing (장수명 주택의 수선교체주기 설정을 위한 BIM활용에 관한 연구)

  • Jeong, Soo-Jin;Park, Jung-Lo;Kim, Ju-Hyung;Kim, Jae-Jun
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2011.11a
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    • pp.147-148
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    • 2011
  • This study applied BIM(Building Information Modeling) technology for Long-life Housing within exterior, interior and building equipment. There has many changes and depression infill material after construction. Therefore to understand establishment of repair and replacement cycle is necessity. In addition, the method of classification is necessary because of construction equipment efficiency. On this study, we will find how can we manage them and establish the repair and repairment cycle by applying BIM technology.

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