• Title/Summary/Keyword: Failure Mode and Effects Analysis

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Introduction of the field - test evaluation system in KEPCO (배전 실증시험장 시스템 현황 소개)

  • Kim, Dong-Myung;Choi, Sun-Kyu;Jang, Sang-Ok;Oh, Jae-Hyoung
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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    • 2004.05a
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    • pp.81-85
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    • 2004
  • This paper describes the testing facility to demonstrate the performance of the distribution class circuit breakers and switchgears and the testing methods. The field-test evaluation system consists of two parts. One is the distribution system for simulation of the condition on interruption mode of switches which are installed in the system and tested by the AFG(Artificial Fault Generator) and the thunderbolt generator just like in the real field. The other is a laboratory for confirmation or the important characteristics regarding to the insulation, gas, environment durability of equipment. For the fatal failure mode, a FMEA(Failure Modes and Effects Analysis) technique which is a kind of a structural analysis to consider a counter-plan was emploved.

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저궤도 상용위성의 시스템 수준 FMECA

  • Lee, Chang-Ho;Cho, Young-Jun
    • Aerospace Engineering and Technology
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    • v.4 no.2
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    • pp.71-78
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    • 2005
  • The purpose of FMECA is to identify parts and design whose damage can effect the mission performance and to improve the spacecraft design using these data. In consequence of this analysis, each failure mode which can be happened during operation and manufacturing period is identified, and their effects on mission performance are reviewed. In this technical report, the FMECA procedures and results for the satellite which is now under development are showed.

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Robust Design for Parts of Induction Bolt Heating System (유도가열시스템의 구성부품에 대한 강건설계)

  • Kim, Doo Hyun;Kim, Sung Chul;Lee, Jong Ho;Kang, Moon Soo;Jeong, Cheon Kee
    • Journal of the Korean Society of Safety
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    • v.36 no.2
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    • pp.10-17
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    • 2021
  • This paper presents the robust design of each component used in the development of an induction bolt heating system for dismantling the high-temperature high-pressure casing heating bolts of turbines in power plants. The induction bolt heating system comprises seven assemblies, namely AC breaker, AC filter, inverter, transformer, work coil, cable, and CT/PT. For each of these assemblies, the various failure modes are identified by the failure mode and effects analysis (FMEA) method, and the causes and effects of these failure modes are presented. In addition, the risk priority numbers are deduced for the individual parts. To ensure robust design, the insulated-gate bipolar transistor (IGBT), switched-mode power supply (SMPS), C/T (adjusting current), capacitor, and coupling are selected. The IGBT is changed to a field-effect transistor (FET) to enhance the voltage applied to the induction heating system, and a dual-safety device is added to the SMPS. For C/T (adjusting current), the turns ratio is adjusted to ensure an appropriate amount of induced current. The capacitor is replaced by a product with heat resistance and durability; further, coupling with a water-resistant structure is improved such that the connecting parts are not easily destroyed. The ground connection is chosen for management priority.

METHOD FOR THE ANALYSIS OF TEMPORAL CHANGE OF PHYSICAL STRUCTURE IN THE INSTRUMENTATION AND CONTROL LIFE-CYCLE

  • Goring, Markus;Fay, Alexander
    • Nuclear Engineering and Technology
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    • v.45 no.5
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    • pp.653-664
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    • 2013
  • The design of computer-based instrumentation and control (I&C) systems is determined by the allocation of I&C functions to I&C systems and components. Due to the characteristics of computer-based technology, component failures can negatively affect several I&C functions, so that the reliability proof of the I&C systems requires the accomplishment of I&C system design analyses throughout the I&C life-cycle. On one hand, this paper proposes the restructuring of the sequential IEC 61513 I&C life-cycle according to the V-model, so as to adequately integrate the concept of verification and validation. On the other hand, based on a metamodel for the modeling of I&C systems, this paper introduces a method for the modeling and analysis of the effects with respect to the superposition of failure combinations and event sequences on the I&C system design, i.e. the temporal change of physical structure is analyzed. In the first step, the method is concerned with the modeling of the I&C systems. In the second step, the method considers the analysis of temporal change of physical structure, which integrates the concepts of the diversity and defense-in-depth analysis, fault tree analysis, event tree analysis, and failure mode and effects analysis.

Development of Accelerated Life Test Method for Constant Electrical Potential Electrolysis Gas Sensor (정전위 전해식 가스센서의 가속수명시험법 개발)

  • Yang, Il Young;Kang, Jun Gu;Yu, Sang Woo;Oh, Geun Tae;Na, Yoon Gyoon
    • Journal of Applied Reliability
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    • v.16 no.3
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    • pp.180-191
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    • 2016
  • Purpose: The purpose of this study was to develop the accelerated life test method for Constant Electrical Potential Electrolysis gas sensor (CEPE gas sensor). Methods: The parts and modules of CEPE gas sensor were analyzed by using Reliability Block Diagram (RBD). Failure Mode and Effect Analysis (FMEA) and Quality Function Deployment (QFD) methods were performed for each part to determine the most affecting stress factor in its life cycle. The long term testing was conducted at three different dry heat levels and the acceleration factor was developed by using Arrhenius relationship. Conclusion: The acceleration factor for CEPE gas sensor was developed by using FMEA, QFD, and statistical analysis for its failure data. Also qualification tests were designed to meet the target life.

Strength of Unidirectional and Fabric Hybrid Laminate Joints (일방향-평직 복합재 혼합 적층판의 체결부 강도 연구)

  • An,Hyeon-Su;Sin,So-Yeong;Gwon,Jin-Hui;Choe,Jin-Ho;Lee,Sang-Gwan;Yang,Seung-Un
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.31 no.1
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    • pp.25-33
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    • 2003
  • The failure load and mode of the unidirectional and fabric hybrid composite laminate joints are studied by test and finite element analysis. Test is conducted for the specimens with nine various geometries under pin loading. Finite element analysis is performed considering the contact and friction effects between the pin and laminate by MSC/NASTRAN. Failure is estimated by Tsai-Wu and Yamada-Sun criteria on the characteristic curve. While the failure of the specimens with the small width and edge length are much affected by the joint geometry, the geometry effects are negligible in the specimens with large width and edge length. Finite element analysis based on the characteristic length method reasonably predicts the failure load and mode of the joints.

Numerical Analysis on External Strengthening Effects in Aged Structures (사용중인 구조물의 보강효과에 대한 해석적 연구)

  • 신승교;임윤묵;김문겸;박동철
    • Proceedings of the Korea Concrete Institute Conference
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    • 2002.05a
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    • pp.455-460
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    • 2002
  • In this study, a numerical analysis that can effectively predict the effect of strengthening of cracked flexural members is developed using axial deformation link elements. Concrete and interface between concrete and repair material are considered as quasi-brittle material. Reinforcing bars and reinforcing steel plates are assumed to perform as elasto-plastic materials. Unloading behavior of axial deformation link element is implemented. In the developed numerical model, a flexural member is intentionally cracked by pre-loading, then, the cracked member is repaired using extra elements, and reloaded. The results from analysis of repaired flexural members agrees well with available experiment results. Also, it was shown that the effect of strengthening and the change of failure mode with respect to the time for strengthening and thickness of repair materials. Based on the results, it was determined that the developed numerical model has a good agreement for determining failure modes and effect of strengthening in cracked flexural members. By utilizing the developed numerical analysis, the time and dimension of external strengthening in an existing cracked flexural member with predition of failure mechanism can be determined.

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Effect of crack location on buckling analysis and SIF of cracked plates under tension

  • Memarzadeh, Parham;Mousavian, Sayedmohammad;Ghehi, Mohammad Hosseini;Zirakian, Tadeh
    • Steel and Composite Structures
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    • v.35 no.2
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    • pp.215-235
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    • 2020
  • Cracks and defects may occur anywhere in a plate under tension. Cracks can affect the buckling stability performance and even the failure mode of the plate. A search of the literature reveals that the reported research has mostly focused on the study of plates with central and small cracks. Considering the effectiveness of cracks on the buckling behavior of plates, this study intends to investigate the effects of some key parameters, i.e., crack size and location as well as the plate aspect ratio and support conditions, on the buckling behavior, stress intensity factor (SIF), and the failure mode (buckling or fracture) in cracked plates under tension. To this end, a sophisticated mathematical code was developed using MATLAB in the frame-work of extended finite element method (XFEM) in order to analyze the buckling stability and collapse of numerous plate models. The results and findings of this research endeavor show that, in addition to the plate aspect ratio and support conditions, careful consideration of the crack location and size can be quite effective in buckling behavior assessment and failure mode prediction as well as SIF evaluation of the cracked plates subjected to tensile loading.

Application of FMECA with Stochastic Approach to Reliability-Centered Maintenance of Electric Power Plants in Korean Power Systems (RCM 수립을 위해 발전설비의 고장확률을 고려한 확률론적 FMECA 평가 기법)

  • Joo, Jae-Myung;Lee, Seung-Hyuk;Kim, Jin-O;Lee, Hyo-Sang
    • Proceedings of the KIEE Conference
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    • 2006.07a
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    • pp.196-197
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    • 2006
  • Preventive maintenance can avail the generation utilities to reduce cost and gain more profit in a competitive supply-side power market. So, it is necessary to perform reliability analysis on the systems in which reliability is essential. In this paper, RCM (Reliability -Centered Maintenance) analytical method is adopted using real historical failure data in Korean power plants. Therefore, the reliability -based Probability model for predicting the failures of components in the power plant is also established, and application to FMECA(Failure Mode Effects and Critical Analysis) consideration of failure probability, Based on the weighting ranking of generating equipments which status to be probability estimation by FMECA. The FMECA is an engineering analysis and a core activity performed by reliability engineers to review the effects of probable failure modes of generating equipments and assemblies of the power system on system performance. The results of this paper show that application of FMECA with stochastic approach to the preventive maintenance can efficiently avail decreasing the cost on maintenance and hence improve the total benefit.

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Reliability Prediction of Hybrid Rocket Ignition System (하이브리드 로켓 점화 장치의 신뢰도 예측)

  • Moon, Keun-Hwan;Moon, Hee-Jang;Choi, Joo-Ho;Kim, Jin-Kon
    • Journal of the Korean Society for Aviation and Aeronautics
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    • v.24 no.4
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    • pp.26-34
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    • 2016
  • In this study, reliability prediction of the ignition system of hybrid rocket is performed. The FMECA is preceded to the reliability prediction. To this end, the ignition system is divided into 5 components and 19 potential failure modes. The failure cause and effects are identified and criticality analysis is carried out for each failure mode, in which the criticality number is estimated using the failure rate databases. Among the numbers, the failure modes and components with higher criticality and severity are chosen and allocated with higher weighting factor. The reliability predictions are performed using the failure rate databases, from which the current ignition system is found to satisfy the target reliability.