共查询到18条相似文献,搜索用时 62 毫秒
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事故树分析中最小割集、最小径集的计算机求解 总被引:4,自引:1,他引:4
袁昌明 《中国计量学院学报》2002,13(4):308-310
运用安全系统工程中事故树最小割集和最小径集的布尔变换法和福赛尔行列法的计算思路,编制了最小割集和最小径集的通用求解程序及其程序的使用方法和注意要点. 相似文献
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真空干燥是硝铵炸药生产过程中一道容易发生燃爆事故的重要工序。为研究硝铵炸药真空干燥过程中发生燃爆事故的原因及机理,通过事故案例分析和现场调研,确定了导致燃爆事故的各个基本事件及其逻辑关系,并由此构建以燃爆事故作为顶事件的事故树。采用布尔代数化简事故树,得到87个最小割集和9个最小径集,结果显示每个最小径集包含的基本事件都较多,说明真空干燥工艺安全性较低。通过计算各基本事件的结构重要度并排序,得到结构重要度较大的基本事件,由此推断出导致燃爆事故的主要基本事件,并有针对性地提出相应的改进措施与建议,为企业的安全生产提供参考。 相似文献
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广西河百高速在施工过程中部分开挖路段需进行爆破开挖,周边有居民房,为确保施工安全,需控制爆破冲击波、爆破振动和爆破飞石等对人员和构筑物的不利影响。采用安全系统工程中事故树分析方法对危险因素展开了系统分析,分别建立了爆破冲击波、爆破振动和爆破飞石事故树,综合分析得到事故树最小割集、事故树最小径集和事故树结构重要度,指出各个因素主次。结果表明:综合爆破冲击波、爆破振动和爆破飞石的事故树分析,在爆破施工过程中要加大施工现场监管、施工设计、减振措施和爆破警戒范围内飞石控制措施等的管理力度。 相似文献
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为帮助海岛爆破工程科学系统化的作业,运用事故树分析法对海岛爆破飞石事故的产生原因进行了分析,建立了爆破飞石事故树图,求出最小割集13个,最小径集8个,得到了基本事件的重要结构度值。结果表明:爆破方案审核不严、现场管理不当等问题是造成海岛爆破飞石事故的主要原因,针对这些基本事件提出了4点预防爆破飞石事故的对策措施,为今后的海岛工程爆破系统作业提供了决策支持。 相似文献
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基于动态故障树的CTCS-3级ATP系统可靠性分析简 总被引:1,自引:0,他引:1
针对传统的可靠性分析方法分析CTCS-3级ATP系统动态失效问题的不足,提出采用动态故障树分析其可靠性。首先,分析系统的结构和功能建立动态故障树模型;其次,采用深度优先最左遍历算法搜索动态故障树模型,得到独立的子树;最后,在引入可修系统可靠性指标基础上,采用解析法和马尔科夫矩阵迭代法求解子树,结合分层迭代方法对动态故障树分析法改进,以减小运算量,使得上述可靠性指标能用于CTCS-3级ATP系统的可靠性评估。计算所得可靠性指标与可靠性框图分析得到的结果对比表明:动态故障树能够更好地描述系统的冗余性和容错性等特点,提高了可靠性指标的精度。 相似文献
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Posbist fault tree analysis of coherent systems 总被引:11,自引:0,他引:11
When the failure probability of a system is extremely small or necessary statistical data from the system is scarce, it is very difficult or impossible to evaluate its reliability and safety with conventional fault tree analysis (FTA) techniques. New techniques are needed to predict and diagnose such a system's failures and evaluate its reliability and safety. In this paper, we first provide a concise overview of FTA. Then, based on the posbist reliability theory, event failure behavior is characterized in the context of possibility measures and the structure function of the posbist fault tree of a coherent system is defined. In addition, we define the AND operator and the OR operator based on the minimal cut of a posbist fault tree. Finally, a model of posbist fault tree analysis (posbist FTA) of coherent systems is presented. The use of the model for quantitative analysis is demonstrated with a real-life safety system. 相似文献
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数控磨床砂轮架系统故障树分析中的一大难点是确定基本事件的发生概率,基本事件的发生情况存在模糊性且由于时间和成本的限制往往无法通过实验获得足够的可靠性数据。为了解决这一问题,引入模糊集合论,用梯形模糊数来描述故障树分析中的基本事件和顶事件的发生概率。首先对数控磨床砂轮架系统的结构层次进行分析,建立砂轮架系统的故障树。然后以砂轮架系统主轴振动异响为例进行模糊故障树分析,求解顶事件发生概率的梯形模糊数;并类比传统故障树分析中"临界重要度"的概念,定义适用于模糊故障树分析的"模糊临界重要度"。最后根据求解的模糊临界重要度对基本事件进行排序,确定危害程度较高的基本事件,结果与企业的实际情况相符合。结果表明该方法能够有效解决数控磨床故障树分析中基本事件难于准确赋值的问题,为企业提高机械系统的可靠性提供了一种定量依据。 相似文献
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Fault tree analysis (FTA) is generally accepted as an efficient method for analyzing system failures. It is well known that a fault tree (FT) is equivalent to a minimal cut set fault tree with all minimal cut-AND structures. The minimal cut-AND structure is an AND conjunction of an output and all inputs that compose a minimal cut set. For the structure, the failed state of the output becomes true when all failed states of inputs exist simultaneously. There are cases where the output of the minimal cut-AND structure depends not only on all failed states of inputs but also on the sequence of occurrences of those failures. This sequential failure logic (SFL) is equivalently expressed with Priority-AND gates in FTA, where inputs to the gates have constant failure and repair rates. A probabilistic model for analysis of SFL was proposed and equations with multiple integration for arbitrary number of inputs were derived from the model. However, it is usually difficult to solve the multiple integration when the number of inputs exceeds a certain range. This paper presents analytical solutions of the probability that the output is in a failed state at time t and the statistically expected number of failures of the output per unit time at time t for the special case where inputs are characterized by common failure and repair rates. In addition, the analysis of FT involving SFL is demonstrated by means of software Mathematica. 相似文献