• Title, Summary, Keyword: Fault Tree

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Fault Tree Construction Method using Function Deployments of Machine Parts (기능 전개를 활용한 기계류 부품의 Fault Tree 구성에 관한 연구)

  • 하성도;이언경;강달모
    • Proceedings of the Korean Reliability Society Conference
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    • pp.257-263
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    • 2001
  • In the analysis of product reliability, the fault tree is widely used since it shows the interrelations of the faults that lead to the product fault. A top-down approach based on experts’ experience is commonly used in the fault tree construction and the trees often take different forms depending on the intent of the analyst. In this work it is studied how to construct fault trees with the utilization of function trees obtained from analyzing the functions and sub-functions of products in order to suggest a generic way of fault tree construction. The function tree of a product is obtained by analyzing basic functions comprising the product main function in a bottom-up approach so that it enables to construct an objective fault tree. The fault tree for a scroll compressor is shown as an example.

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A Methodology for Constructing Function Tree & Fault Tree in Reliability Analysis (신뢰성 분석을 위한 Function Tree 및 Fault Tree 구성 방법에 관한 연구)

  • Ha, Sung-Do;Lee, Eon-Kyung;Kang, Dal-Mo
    • Proceedings of the KSME Conference
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    • pp.333-338
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    • 2001
  • Fault tree is a widely used methodology for analyzing product reliability. The fault trees are usually constructed using the experiences of expert reliability engineers in top-down approaches and have different structures according to each expert's subjectivity. In this work it is tried to find a general method for the fault tree construction based on the function tree that is the result of product function deployment. Based on the function tree, the method has the advantage of resulting an objective fault tree since the faults are defined as the opposite concept of functions. The fault tree construction of this work consists of the following steps: 1) definition of product primary function with the viewpoints of product operation and configuration, 2) construction of functional relation chart using a grouping algorithm, 3) abstraction of functional block diagram according to operation sequences and configuration of a product, 4) construction of function tree for each viewpoint, and 5) construction of fault tree by matching the function tree and simplification of the result.

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A Study on the Construction of Function Tree using Function Deployment (기능 전개 결과를 이용한 Function Tree 구성에 관한 연구)

  • 하성도;이언경;박선주;강달모
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.401-406
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    • 2000
  • Fault tree analysis (FTA) is a widely used methodology for reliability analysis. The method is useful in that it suggests a very comprehensive way of describing the hierarchical relations of causes of faults and the corresponding results. However it is difficult to get appropriate fault trees for given products or systems without very profound knowledge and experience. This work aims to develop a methodology of fault tree construction using the results of function deployment for machine parts, which provides an objective way of preparing fault trees. The failure modes are defined to each function network generated by the function deployment method and the fault tree with respect to each viewpoint is constructed by arranging the failure modes. The fault tree is finally obtained by synthesizing the fault trees with respect to each viewpoint. The example of fault tree construction is also shown.

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One-time Traversal Algorithm to Search Modules in a Fault Tree for the Risk Analysis of Safety-critical Systems (안전필수 계통의 리스크 평가를 위한 일회 순회 고장수목 모듈 검색 알고리즘)

  • Jung, Woo Sik
    • Journal of the Korean Society of Safety
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    • v.30 no.3
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    • pp.100-106
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    • 2015
  • A module or independent subtree is a part of a fault tree whose child gates or basic events are not repeated in the remaining part of the fault tree. Modules are necessarily employed in order to reduce the computational costs of fault tree quantification. This quantification generates fault tree solutions such as minimal cut sets, minimal path sets, or binary decision diagrams (BDDs), and then, calculates top event probability and importance measures. This paper presents a new linear time algorithm to detect modules of large fault trees. It is shown through benchmark tests that the new method proposed in this study can very quickly detect the modules of a huge fault tree. It is recommended that this method be implemented into fault tree solvers for efficient probabilistic safety assessment (PSA) of nuclear power plants.

Development of Automatic Fault Tree Construction System using Digraph (Digraph를 이용한 Fault Tree 자동합성시스템의 개발)

  • Jung, Won-Seok;Lee, Geun-Won;Moon, Il
    • 제어로봇시스템학회:학술대회논문집
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    • pp.393-393
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    • 2000
  • FTA(Fault Tree Analysis) is a safety analysis method that focuses on one particular accident or main system failure and provides a method of determining causes of that event. While most of the statistical and cut set analysis have been automated, actual construction of the fault-tree is usually done manually. Manual construction of the fault-tree is extremely time consuming and it requires high level of expertise and experience. In addition to the time involved, different analyst often produces different fault-trees either by incorrect logic or omission of certain events. Automatic fault-tree construction system can be efficient in solving above problems. This study presents a new Digraph-FT conversion algorithm that leads automatic FTA system.

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Reliability Assessment of Railway Power System by using Tree Architecture (Tree 구조를 이용한 전철급전시스템의 신뢰도 평가)

  • Cha, Jun-Min;Ku, Bon-Hui
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.59 no.1
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    • pp.9-15
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    • 2010
  • As catenary supply electric power directly to the railway system, it is very important to prevent an accident of a catenary for appropriate train operation. This paper proposed the assessment the outage data for "British Catenary Safety Analysis Report" and Korean data to compare the reliability of the railway system. The analyzed data were applied to Event Tree and Fault Tree algorithm to calculate the reliability indices of railway system. Event tree is created and gate results of fault tree analysis are used as the source of event tree probabilities. Fault tree represents the interaction of failures and basic events within a system. Event Tree and Fault Tree analysis result is helpful to assess the reliability to interpreted. The reliability indices can be used to determine the equipment to be replaced for the entire system reliability improvement.

A System Approach to A Bag Filter Failure using Fault Tree Analysis (Fault Tree Analysis을 활용한 집진기(Bag Filter) 고장의 체계적 분석)

  • 이근희;이동형
    • Journal of the Society of Korea Industrial and Systems Engineering
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    • v.12 no.20
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    • pp.1-24
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    • 1989
  • This paper takes aim at the reliability evaluation by application of Fault Tree Analysis and its computerization. FTA is one of the methods for evaluation of system reliability and safety analysis. The important characteristic of this paper is that computer program is written in the package program(dBaseIII+) by 16Bit/AT personal computer. The program consists of three program segments. (1) The minimal cut sets of the system fault tree are obtained by means of "Fault tree reduction algorithm" (2) The minimal path sets are obtained by inversion of the minimal cut sets determined from fault tree (3) The importance of the basic events which are presented in the minimal cut sets is obtained by means of structural importance analysis. In this paper, a Fault Tree Analysis is applied to a BAG FILTER which is a kind of dust collector.collector.

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A Review of FTA Methods for FT Construction & Evaluation(I) (FT구축 및 평가를 위한 FTA방법의 일반적 고찰(I))

  • 박주식;김길동;강경식;박상민
    • Journal of the Korea Safety Management and Science
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    • v.2 no.3
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    • pp.13-25
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    • 2000
  • This paper reviews and classify fault-tree analysis methods developed since 1960 for system safety and reliability. Fault-tree analysis is a useful analytic tool for the reliability and safety of complex systems. The literature on fault-tree analysis is, for the most part, scattered through conference proceedings and company reports. This paper classify the literature according to system definition, fault-tree construction, qualitative evaluation, quantitative evaluation, and available computer codes for fault-tree analysis.

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A study in fault detection and diagnosis of induction motor by clustering and fuzzy fault tree (클러스터링과 fuzzy fault tree를 이용한 유도전동기 고장 검출과 진단에 관한 연구)

  • Lee, Seong-Hwan;Shin, Hyeon-Ik;Kang, Sin-Jun;Woo, Cheon-Hui;Woo, Gwang-Bang
    • Journal of Institute of Control, Robotics and Systems
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    • v.4 no.1
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    • pp.123-133
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    • 1998
  • In this paper, an algorithm of fault detection and diagnosis during operation of induction motors under the condition of various loads and rates is investigated. For this purpose, the spectrum pattern of input currents is used in monitoring the state of induction motors, and by clustering the spectrum pattern of input currents, the newly occurrence of spectrum patterns caused by faults are detected. For the diagnosis of the fault detected, a fuzzy fault tree is designed, and the fuzzy relation equation representing the relation between an induction motor fault and each fault type, is solved. The solution of the fuzzy relation equation shows the possibility of occurence of each fault. The results obtained are summarized as follows : (1) Using clustering algorithm by unsupervised learning, an on-line fault detection method unaffected by the characteristics of loads and rates is implemented, and the degree of dependency for experts during fault detection is reduced. (2) With the fuzzy fault tree, the fault diagnosis process become systematic and expandable to the whole system, and the diagnosis for sub-systems can be made as an object-oriented module.

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A Study on System's Reliability Evaluation Using DFT Algorithm (동적 결함 트리 (Dynamic Fault Tree) 알고리즘을 이용한 시스템의 신뢰도 평가에 관한 연구)

  • 김진수;양성현;이기서
    • Proceedings of the KSR Conference
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    • pp.280-287
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    • 1998
  • In this paper, Dynamic Fault Tree algorithm(DFT algorithm) is presented. This new algorithm provides a concise representation of dynamic fault tolerance system structure with redundancy, dynamic redundancy management and complex fault & error recovery techniques. And it allows the modeler to define a dynamic fault tree model with the relative advantages of both fault tree and Markov models that captures the system structure and dynamic behavior. This algorithm applies to TMR and Dual-Duplex systems with the dynamic behavior and show that this algorithm captured the dynamic behavior in these systems with fault & error recovery technique, sequence-dependent failures and the use dynamic spare. The DFT algorithm for solving the problems of the systems is more effective than the Markov and Fault tree analysis model.

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