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In this paper, the potential risk of undesirable events occurring during tunneling with application of a shield tunnel boring machine (TBM) method is discussed along with the risk analysis which can systematically assess overall risk levels. Potential risks and typical scenarios pertaining to shield TBM tunnels have been investigated based on previous case histories and correspondence with experts. The relevant risks from undesirable events were categorized into four groups: cutter-related malfunction, machine blockage or hold-up, mucking problems that hinder transporting excavated materials, and segment defects. A fault-tree set was constructed by grouping risk factors (or causes) into geological, design and construction/management factors. Risk analysis was performed by adopting fault-tree analysis (FTA) and an analytic hierarchy process (AHP) with consideration of the probability and impact of the risks. In addition, the proposed method was reliably validated by comparison with field observation, and thus indicates its applicability to risk management for shield TBM tunneling. 相似文献
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Shuen-Ren Cheng Binshan Lin Bi-Min Hsu Ming-Hung Shu 《Expert systems with applications》2009,36(9):11918-11924
Natural gas, one of the cleanest, most efficient and useful of all energy sources, is a vital component of the world’s supply of energy. To make natural gas more convenient for storage and transportation, it is refined and condensed into a liquid called liquefied natural gas (LNG). In a LNG site, safety is a long-team and critical issue. The emergency shutdown (ESD) system in the LNG receiving terminal is used to automatically stop the pumps and isolate the leakage section. Fault-tree analysis (FTA) has been widely used for providing logical functional relationships among subsystems and components of a system and identifying the root causes of the undesired failures in a system. In the conventional FTA for the ESD system, we usually assume that exact failure probabilities of events are collected. However, in most real applications, first, the FTA for the ESD system needs to be made at a early design or manufacturing stage, certain new components normally used without failure data; secondly, sometimes the environmental change in the system during the operation periods. This makes more difficult to gather past exact failures data for the FTA. To complete the FTA of the ESD system under these uncertain situations, we apply the intuitionistic fuzzy sets (IFS) theory to the FTA. We generate the intuitionistic fuzzy fault-tree interval, and the intuitionistic fuzzy reliability interval for the ESD system. We also present an algorithm to find the critical components in the system based on IFS–FTA and determine weak paths in the ESD system, where the key improvement must be made. 相似文献
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A. Bobbio E. Ciancamerla G. Franceschinis R. Gaeta M. Minichino L. Portinale 《Reliability Engineering & System Safety》2003,81(3):269
This paper shows how heterogeneous stochastic modelling techniques of increasing modelling power can be applied to assess the safety of a digital control system. First, a Fault-Tree (FT) has been built to model the system, assuming two-state components and independent failures. Then, the FT is automatically converted into a Bayesian Network, allowing to include more modelling details and localized dependencies. Finally, in order to accommodate repair activities and perform an availability analysis, the FT is converted into a Stochastic Petri Net (SPN). Moving from a combinatorial model (the FT) to a state space based model (the SPN) increases the modelling flexibility, but incurs into the state space explosion problem. In order to alleviate the state space explosion problem, this paper resorts to the use of a particular type of high level (coloured) Petri nets called SWN. A digital control system is considered as a case study, and safety measures have been evaluated, referring to the emergent standard IEC 61508. 相似文献
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针对传统故障树生成与诊断方法过于复杂的问题,提出了一套适合工程实践用的故障树生成及诊断模型.利用虚拟仪器技术研制了可视化的故障树自动生成与诊断软件,并利用该软件程序自动调用相应的虚拟仪器完成对该检测点的测试和诊断.实际应用表明,该方法满足设计要求,可无缝移植到其他数字化仪器设备的故障诊断过程中. 相似文献
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Shi-Ning Ju Cheng-Liang Chen Chuei-Tin Chang 《Reliability Engineering & System Safety》2003,81(2):163-181
The development of a systematic fault-tree synthesis procedure for the override control systems is presented in this paper. The unique configuration of the digraph model under study is first described and then analyzed in detail. On the basis of qualitative simulation of the fault propagation patterns, the corresponding generalized fault-tree structures are then established. It can be observed clearly from the simulation results that none of the existing techniques are capable of producing the correct fault-trees. To demonstrate the correctness of our analysis, successful application of the proposed structure to furnace operation is also presented. 相似文献
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A procedure for the failure cause identification of tribo-mechanical systems is presented based on fault-tree using a digraph approach. A variable-event system digraph for a tribo-mechanical system is suggested which takes into account structure of the system. A top event or undesirable event for the system is then defined and the fault-tree for this top event is deduced from the digraph by back-tracking it. The analysis of the fault-tree aids the design and practising engineers in design and development of reliable, safe and productive tribo-mechanical systems. The methodology is applied to journal bearing oil supply system in a power plant application. 相似文献
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文章用故障树分析方法对秦山核电厂高压安注系统的可靠性进行了分析。这项工作是采用西德反应堆安全研究所(GRS)研制的RALLY程序包进行的,内容包括系统不可用度计算、不确定度分析、统计评估以及重要度分析。有关分析结果为寻找秦山厂高压安注系统的薄弱环节、改进系统设计提供了参考依据。 相似文献