• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집
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• pp.162-168
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• 2009

FMEA(Failure Mode and Effect Analysis) is a failure analysis method for the system to identify the potential failure modes, and their effects and causes to reduce or mitigate the critical effects of the system. FMEA for railway was introduced with reliability of railway system, and this was used for identifying and analysing the possible hazards qualitatively to meet the requirements in early stage of business. In general, the overall failure data of system could be managed from design stage by FMEA, and also the countermeasures to prevent many predicted failures could be established by identification of failure modes and assement of failure effects by FMEA. Using these advantages of FMEA, the effectiveness of reliability improvement could be expected if FMEA is applied continuously in operation stage. It is essential that railway vehicles are maintained with high level of safety and reliability not to happen any failures in operation. This paper is proposed the proper FMEA for maintenance of railway vehicles compared with existing FMEA.

• 대한기계학회논문집A
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• 제39권6호
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• pp.631-638
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• 2015

본 연구에서는 고체 로켓 추진 기관의 신뢰성 분석을 위해 준-정량적 FMECA를 수행하였다. 준-정량적 FMECA는 고장모드 및 영향 분석(FMEA)과 치명도 분석(CA)를 포함하는 분석 기법으로서, FMECA 수행을 위해서 FMEA는 고체 로켓 추진 기관을 43개의 부품으로 나누어 각 부품에 대하여 도출된 총 137개의 고장모드에 대해 수행하였다. 또한 일부 고장모드의 고장률 데이터를 이용하여 치명도 분석을 수행하였다. 준-정량적 FMECA 수행을 통하여 고체 로켓 추진 기관의 각 부품에서 발생 할 수 있는 잠재적 고장모드와 고장원인 및 영향을 분석, 정리할 수 있었으며, 우선적인 개선 조치가 필요한 중요 고장모드를 확인할 수 있었다.

• 한국안전학회지
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• 제38권5호
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• pp.43-50
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• 2023

With the advent of industrialization, consumers and end-users demand more reliable products. Meeting these demands requires a comprehensive approach, involving tasks such as market information collection, planning, reliable raw material procurement, accurate reliability design, and prediction, including various reliability tests. Moreover, this encompasses aspects like reliability management during manufacturing, operational maintenance, and systematic failure information collection, interpretation, and feedback. Improving product reliability requires prioritizing it from the initial development stage. Failure mode and effect analysis (FMEA) is a widely used method to increase product reliability. In this study, we reanalyzed using the FMEA method and proposed an improved method. Domestic railways lack an accurate measurement method or system for maintenance, so maintenance decisions rely on the opinions of experienced personnel, based on their experience with past faults. However, the current selection method is flawed as it relies on human experience and memory capacity, which are limited and ineffective. Therefore, in this study, we further specify qualitative contents to systematically accumulate failure modes based on the Failure Modes Table and create a standardized form based on the Master FMEA form to newly systematize it.

• 한국신뢰성학회지:신뢰성응용연구
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• 제10권2호
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• pp.123-135
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• 2010

Failure mode and effects analysis (FMEA) is a widely used technique to assess or to improve reliability of products or processes at early stage of development. Traditionally, the prioritization of failures for corrective actions is performed by evaluating risk priority numbers (RPN). In practice, due to insufficient evaluation criteria specific to related products and processes, RPN is not always evaluated properly. This paper reestablishes an effective methodology for prioritization of failure modes in FMEA procedure. Revised evaluation criteria of RPN are devised and a refined FMEA sheet is introduced. To verify the proposed methodology, it is applied to inspection processes of PCB products.

• 한국해양공학회지
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• 제23권6호
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• pp.32-38
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• 2009

An FMEA for the waterjet-lifter of a DSNM is performed to prevent the occurrence of device failure. A waterjet-lifter raises and transports manganese nodules from the deep-sea floor up to a somewhat elevated place, from which a pin-scraper transports the lifted nodules to the inner space of the DSNM. A concept design for a device using the axiomatic design methodology is shown as the mapping between the functional domain and physical domain. The FMEA for a DSNM is introduced briefly and the rating criteria of severity, occurrence, and detection for the DSNM are defined. The FMEA of the functional requirements of a DSNM device is accomplished. Three kinds of failure modes, as well as their effects and causes, are predicted. Current design control methods for detecting potential failures, such as physical or computational experiments, design confirmation, and mathematical calculation, are described and the recommended actions for several significant causes are suggested.

• 전기전자학회논문지
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• 제23권1호
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• pp.254-260
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• 2019

본 논문에서는 양방향 dc-to-dc 컨버터의 고장원인, 고장영향, 고장 결과를 파악하기 위한 failure mode and effect analysis(FMEA)와 양방향 컨버터의 위험도를 고려한 fault-tree analysis(FTA)를 통해 고장률을 예측한다. 전기차의 구동전압을 효율적으로 상승시키기 위해 인버터 앞단에 부착되는 양방향 컨버터는 배터리 전력을 dc-link 커패시터로 방전시키는 승압모드와 회생전력을 배터리로 충전시키는 강압모드를 가진다. 양방향 컨버터의 동작 특성을 고려한 FMEA 결과를 바탕으로 컨버터의 위험도를 고려한 고장나무를 설계한다. 전기차 MCU용에 맞는 설계 파라메타를 설정하고 출력전압 리플과 인덕터 전류 리플에 따른 커패시터와 인덕터의 부품 고장률을 분석한다. 또한 동작 온도에 따른 주요부품의 고장률을 MIL-HDBK-217F를 이용하여 구한다. 마지막으로 부품 고장률을 고장나무의 기본 사상의 고장률로 반영하여 컨버터 고장률과 평균고장시간을 예측한다.

• 한국안전학회지
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• 제30권5호
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• pp.108-113
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• 2015

Plastic injection moulding machine is widely used for many industrial field. It is classified into mandatory safety certification machinery in Industrial Safety and Health Act because of its high hazard. In order to prevent industrial accidents by plastic injection moulding machine, it is necessary for designer to identify hazardous factors and assess the failure modes to mitigate them. This study tabulates the failure modes of main parts of plastic injection moulding machine and how their failure has affect on the machine being considered. Failure Mode & Effect Analysis(FMEA) method has been used to assess the hazard on plastic injection moulding machine. Risk and risk priority number(RPN) has been calculated in order to estimate the hazard of failures using severity, probability and detection. Accidents caused by plastic injection moulding machine is compared with the RPN which was estimated by main regions such as injection unit, clamping unit, hydraulic and system units to find out the most dangerous region. As the results, the order of RPN is injection unit, clamping unit, hydraulic unit and system units. Barrel is the most dangerous part in the plastic injection moulding machine.

• 산업경영시스템학회지
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• 제31권4호
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• pp.162-167
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• 2008

FMEA (failure mode and effect analysis)is a widely used technique to assess or to improve reliability of product not only at early stage of design and development, but at the process and service phase during the product life cycle. In designing a service system, this study proposes a fuzzy service FMEA with the service blueprints as a tool which describes customer actions, onstage contact employees actions, backstage contact employees actions, support processes, and physical evidences, in order to analyse and inform service delivery system design. We fuzzified only two risk factors, occurrence and severity, to more effectively assess the potential failure modes in service. Proposed fuzzy risk grades are applied to Gaussian membership function, defuzzified into Fuzzy Inference System, and eventually identified the ranks on the potential fail points.

• 산업기술연구
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• 제33권A호
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• pp.9-14
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• 2013

Reliability plays a pivotal role in the development of medical instruments. A hyperbaric oxygen chamber, as a medical/health device, is known to help medical therapy for diversity of diseases through provision of high purity oxygen. The use of hyperbaric oxygen chamber is expected to increase in the future and study to examine reliability and safety is needed. We have performed reliability assessment for a newly developed hyperbaric oxygen chamber in this study. We first briefly discussed the system structure and mechanism. We then performed FMEA (Failure Mode and Effect Analysis) for the chamber. We drew major failure modes affecting the system performance and performed in depth analysis for measuring the expected effects.

• 한국신뢰성학회지:신뢰성응용연구
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• 제16권2호
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• pp.162-170
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• 2016

Purpose: The purpose of this study was to analyze the failure modes of an auto transfer switch (ATS), determine the most common failure mechanisms, and iterate the design to improve reliability. Methods: We carried out failure mode and effect analysis (FMEA) to determine the failure modes and mechanisms. We identified the parts or modules that required improvement via two-stage quality function deployment based on FMEA, and improvements to reliability were monitored using the Gomperz growth model. Results: The main failure modes of the ATS were damage to, and deformation of, the stator / movable element due to repetitive movements. Five iterations of design modification were carried out, and the mean time to failure (MTTF) increased to 14,539 cycles, corresponding to 85% of the target MTTF. The Gompertz growth model indicates that the 10th iteration of design modification is expected to achieve the target MTTF. Conclusion: We improved the reliability of mechanical parts via failure mode analysis, and characterized the iterative improvements in the MTTF using the Gompertz growth model.