• 전기학회논문지
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• 제62권8호
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• pp.1177-1183
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• 2013

In this paper, the analysis of inspection period bases on reliability is suggested in the field of traction power system. Even though there are several maintenance models, the most commonly used maintenance assessment has been focused on time based maintenance in real traction power systems. The maintenance intervals are selected on the basis of long-time experience. It ensures high availability and exact planning of staff. Reliability centered maintenance, which evaluates criticality and severity of each failure mode, achieves the operation, maintenance, and cost-effective improvement that will manage the risks of equipment. This paper deals with electrification in railway inspection frequency and applied reliability based inspection frequency instead of constant intervals. The distribution function of failure rate in traction power system belongs to Weibull function. Also, the fault data and the number of installed equipments for electrifications are collected. The failure history is investigated and classified in detail. Though these complicated procedures, it contribute to extend equipment lifetime and to reduce maintenance costs.

• 한국전자통신학회논문지
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• 제6권6호
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• pp.881-887
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• 2011

미국을 비롯한 선진국들은 배치 운용중인 개발 무기체계의 야전 운용자료를 수집 분석하여 신뢰도 유지여부를 확인하고 설계 재반영, 군수지원 요소 최적화를 위한 기초 경험자료 등으로 잘 활용하고 있으나 국내에서는 적용이 미흡한 실정이다. 따라서 본 논문에서는 국내 연구개발후 함정에 배치 운용 중인 ${\bigcirc}{\bigcirc}$대함유도탄을 대상으로 최근 6년간 ${\bigcirc}{\bigcirc}{\bigcirc}$발에 대한 구성품별 고장현황 등이 포함된 야전 운용자료를 수집하여 Weibull++ v7 소프트웨어에 입력후 모수적 추정방법을 이용하여 신뢰도를 분석하였다. 분석결과를 개발단계에서 분석된 유도탄과 구성품별 MTBF와 비교하여 초기신뢰도 유지여부를 분석하였고, 고장패턴과 검사주기 적절성도 확인하였다. 도출결과를 개발기관 및 품질보증기관, 제작사에 환류하여 RCM 분석을 통한 초기 신뢰도 회복 조치 및 총수명주기간 유지보수비가 절감되도록 정비정책에 대한 개선방안을 제시하였다.

• 한국신뢰성학회지:신뢰성응용연구
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• 제10권4호
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• pp.265-278
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• 2010

Module of the LED traffic signal is the core component for the care of driver and walker. Also it is important one to control the traffic. If it is against the criteria of brightness, it is the source of the people's death and traffic congestion. Therefore, it is a list of articles desired the security of stability. However, there is not the analysis of failure and not preserve the uniformity of quality. Therefore, it is necessary to establish the criteria of appreciation for the module of the LED traffic signal to analysis the data of failure. In this paper, we investigate the performance test, environment field test and test of reliability appreciation to improve the reliability. We also set up the criteria of success decision using the real measurement data.

• Corrosion Science and Technology
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• 제3권5호
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• pp.209-215
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• 2004

Flexible hydraulic hose assembly that consists of hose and joints is used widely on various construction heavy equipments, agricultural machines, motor vehicles, and industrial heavy machines that require flexibility on hydraulic pipelines. It is classified by the maximum usage pressure which is determined by the winding layers of coiling steel wire and the inner diameter of the hoses. In this paper, we designed and performed an accelerated life test for assessing the reliability of a flexible hydraulic hose assembly. In the proposed accelerated life test, typical impulse pressure testing method is applied with the half omega flexing operation to simulate the practical flexing motion of the hose assembly.

• 산업경영시스템학회지
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• 제35권2호
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• pp.71-79
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• 2012

In this paper, an evaluation of a product replacement ratio of irreparable items to the normally working ones is performed with a view to a warranty analysis. It is demonstrated that the replacement ratio during the warranty period can be estimated from the field data collected during the period of operation, and one can provide the management with a useful information regarding the appropriateness for the warranty period, which is vital to the product marketing strategy. Although warranty data usually take the form of multiply right censored interval data, the conventional reliability analysis method seems to be good enough as in this case. More sophisticated method such as warranty cost analysis and 2-dimensional warranty analysis is yet desired.

• 한국자동차공학회논문집
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• 제2권6호
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• pp.1-8
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• 1994

To enhance the strength of gears for transmission, Generally caburizing heat treatment is applied. But there are some problems in this technology the distortion of gears during heat treatment process, and the discontinuity of manufacturing process. For these reasons, the high frequency induction hardening process is widely used. This method is one of the surface hardening process to improve the wear resistance and fatigue life of the machine components. In this study, to compare the bending fatigue strength of caburized gear with that of induction hardened gear, bending fatigue testing of gears with two different cases was performed by using an electrohydraulic servo-controlled fatigue testing machine and double tooth bending fatigue test fixture. Fatigue life distributions at constant stress levels were established directly from fatigue data. For gear design, the fatigue strength distribution at specified life is more important. This distribution is obtained by statical transformation from fatigue life distribution. Reliability of bending fatigue strength was estimated by P-S-N curves and Weibull distribution.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.394-399
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• 2004

Increased cumulative running times of railroad vehicle brings out such degradation as wear and fatigue. It don't adapt corrective maintenance which repairs a poor pan after a trouble but use preventive maintenance which fixes a bad part before a trouble. There were a few researches for preventive maintenance such as inspect affairs and facilities management. They couldn't estimate the operation reliability on railroad vehicle. Therefore, this study proposes the preventive maintenance procedure that predict repair period of end beam for uncovered freight car using reliability function and instantaneous failure rate on the basis of fatigue test and load history data.

• 산업경영시스템학회지
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• 제33권4호
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• pp.209-217
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• 2010

Reliability tools such as QFD and FMEA identify voice of customer related to product design, its use, how failures may occur, the severity of such failures, and the probability of the failure occurring. With these identified items, a development team can focus on the design process and the major issues facing the product in its potential use environment for the customer. The purpose of this research is to develop a reliability estimation process of agricultural machinery components using QFD, FMEA, and field failure data. Based on QFD method, customer requirements, engineering design elements and part characteristics were deployed. Using the field failure data, failures are investigated, and Weibull B10 life are estimated. This estimation process is useful for preparing the design input and planning the durability target.

• 한국생산제조학회지
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• 제9권4호
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• pp.147-153
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• 2000

This paper presents a design method using CAE(Computer Aided Engineering ) with the consideration of reliability for optimal gear driving system. This method considered a configuration of the intermediate shaft. There are four mounting types, such as double straddle, double overhung, output gear overhung, and input ger overhung in the intermediate shaft. The reliability and life analysis are based on the two-parameter Weigbull distribution lives of the gears and bearing . The validity and feasibility of the proposed method are verified by the application to transmission of a industry machine.

• 조명전기설비학회논문지
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• 제29권7호
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• pp.71-79
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• 2015

This paper is on the development of computer software which can be utilized as a power system analysis tool for reliability assessment education. The input data of the developed software are so simple that even a non-expert easily understand how to use it. The software provides not only reliability indices but also their distributions, moreover, it provides the factors those effect the indices, which made the software even more useful for educational purpose. The developed software utilized Monte-carlo simulation based on the state duration sampling, therefore it can manage various probability distributions such as exponential, Weibull, gamma and lognormal distribution. Within the software, the parameters of the distribution can be decided automatically from its mean and variance, that is another advantage as an educational software.