• Journal of the Korean Society for Railway
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• v.15 no.6
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• pp.550-557
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• 2012

In general, FMECA is a technique for identifying failure modes and devices which could result in fatal outcomes. Also it can be used in design or in maintenance through establishing priorities. The purpose of this paper is aimed at improving the driving conditions in advance through analyzing the operation failure phenomena quantitatively with FMECA analysis on the onboard signal system equipped with ATC/ATO, and through deriving the risk factors. This paper suggests an alternative solution for improving the performance of ADU by analyzing a case with FMECA.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.6
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• pp.781-787
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• 2010

Forecasting possible failure characteristics is very important in maintenance planning because it helps in predicting any future failures and determining the optimum replacement interval. This paper examines the time.to-failure distribution of the transfer gearbox of a J79 engine by using a probability plotting technique which is one of the most convenient techniques for reliability analysis. Various probability distributions are evaluated for determining the suitable probability distribution of the failure data of the transfer gearbox, and the resulting correlation coefficient indicates that failure data have a lognormal distribution. The expected number of unscheduled maintenance actions and the optimum replacement interval for various values of cost ratios are determined.

• Proceedings of the Korean Reliability Society Conference
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• 2004.07a
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• pp.313-333
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• 2004

품질개선 활동의 효율성 평가(년도별 제품의 신뢰성 추이관찰), 부품 개선효과 예측 및 판단, 주요 부품에 대한 고장 모드별 형상 모수 파악$\rightarrow$가속수명 설계 활용, 신제품 개발시 신뢰성 목표 수립 및 양산제품의 개선 목표 설정(중략)

• Bulletin of the Korean Space Science Society
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• 2007.10a
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• pp.83.2-83.2
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• 2007

• Journal of the Korean Society for Railway
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• v.10 no.5
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• pp.520-526
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• 2007

본 논문에서는 한국형 틸팅열차의 유지보수 활동을 위해 신뢰성기반유지보수체계를 제안하였다. 열차시스템을 3단계의 교체 부품 단위로 분류하고, 각 단위에 대해 기능블록도를 작성한 후 고장모드 영향 분석을 실시하였다. 각 단위의 심각도를 결정한 후 유지보수 정책을 제안하였으며, 틸팅열차를 위한 유지보수 기준을 정하고, 실제 사례를 제시하였다. 제안된 신뢰성기반유지보수체계는 기존 유지보수 체계와도 호환성을 갖고 있으며, 안전성 향상과 유지보수 활동 효율화에 기여할 수 있다.In this paper, a reliability centered maintenance (RCM) system is proposed to perform maintenance action for Korean Tilting Train. The train system was divided into line replaceable units up to three steps. Functional block diagrams were drawn and failure mode effect analysis for the units was carried out. The criticality of each unit was determined and a maintenance policy was proposed. Maintenance and repair criteria for the tilting train were determined and an example was presented. The proposed RCM system is compatible with the previous maintenance system and contributes to improvement of safety and efficiency of maintenance action.

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.251-261
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• 2006

FMEA(Failure Mode and Effects) is a procedure for the analysis of a system to identify the potential failure modes, and their effects and causes to reduce or mitigate the critical effects of the system. Recently, FMEA is used in various industries and it is specialized in each industry. For instance, MIL-1629a in Military industry, SAE-J1739 in Automotive industry and other industry are using specialized FMEA method. Though Railroad industry requires the high reliability system, it does not have the FMEA method which is specialized to them. So in this paper, we examined the MIL-1629a, SAE-J1739, IEC-60812 and compared those standards. Furthermore, we propose the FMEA method that is specialized to the railroad system.

• Journal of the Korean Society for Precision Engineering
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• v.31 no.1
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• pp.67-73
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• 2014

A reliability evaluation or prediction can be defined as MTBF which stands for mean time between failures (Exclusively for repairable failures). Spindle system has huge effect on performance of machine tools and working quality as well as is required of high reliability. Especially, it takes great importance in producing automobiles which includes a large number of working processes. However, it is unusually difficult to predict reliability because there are lack of data and research about reliability of spindle system. Standards and methods of examinations for reliability evaluation of machine tools are scarce at local and abroad as well. Therefore, this research is meant to improve the reliability of spindle system before mass produced with developing standards of reliability and methods of examinations through FMEA to assess reliability of spindle system in prototype stages of developing high speed spindle system of machining center.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.324-327
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• 2001

This paper shows an example of the Design Review and Common-Cause Failure (CCF) Modeling of mechanical Parts. Reliability should be continuously monitored during the entire period of design. Design Review is the procedure to improve the reliability for the product. We proposed the reliability assessment and design review method. CCF Model is the general dependent model considering the failure mode effects several component simultaneously. This study considers the computation of the network with dependent components. It is important that CCF model is applied for mechanical pars.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.10
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• pp.4762-4767
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• 2012

The AF track circuit that detecting train position and transmitting various train control data for DTG to the train on-board is composed of single operation system. If a failure occurs on this system, the driver should be operate the train by manually until the system is restored, because the system cannot control switch machines and signals by automatically. In this process the human error affects to the train delay, collision, derailment and critical safety accident. Therefore, this document has analyzed the effects that each failure mode influences on system and train, and quantified the failure valuation point and class. Basis on this quantified analysis result, MTBF increased and MTTR decreased and failure number also decreased by adopting the independent installation of power supply, the replacement of defected capacitors, the installation of resister cooling system and the improvement of maintenance methods. And the failure factors of AF track circuits were decreased by conducting the preventive maintenance which is a quantitative way of maintenance system by experience.

• Journal of the Korean Society for Nondestructive Testing
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• v.21 no.6
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• pp.618-629
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• 2001

This paper presents a result of failure analysis and reliability evaluation for high voltage ceramic capacitors. The failure modes and failure mechanisms were studied in two ways in order to estimate component life and failure rate. The causes of failure mechanisms for zero resistance phenomena under withstanding voltage test in high voltage ceramic capacitors molded by epoxy resin were studied by establishing an effective root cause failure analysis. Particular emphasis was placed on breakdown phenomena at the ceramic-epoxy interface. The validity of the results in this study was confirmed by the results of accelerated testing. Thermal cycling test for high voltage ceramic capacitor mounted on a magnetron were implemented. Delamination between ceramic and epoxy, which might cause electrical short in underlying circuitry, can occur during curing or thermal cycle. The results can be conveniently used to quickly identify defective lots, determine $B_{10}$ life estimation each lot at the level of inspection, and detect major changes in the vendors processes. Also, the condition for dielectric breakdown was investigated for the estimation of failure rate with load-strength interference model.