燃气输配管网可靠性的故障树分析

对引起管网失效的各个因素进行系统分析，建立了燃气输配管网失效故障树，对该故障树进行了定性和定量分析。     

基于FFTA城市燃气输配系统安全评估探讨

采用故障树分析方法对城市燃气输配系统的故障树模型进行定性和定量失效分析。针对系统的事件发生概率不确定情况,将模糊数学引入到故障树分析方法,给出了输配系统的模糊故障树安全评估方法。计算表明,该方法用于输配系统的安全评估是行之有效的。     

基于故障树的汽车起重机起升机构故障分析

为了定量评价汽车起重机液压系统中的起升系统的可靠性,了解液压汽车起重机的起升系统各部件失效的概率大小,以确定系统各部件的薄弱环节,确保液压汽车起重机的安全运行,本文以QY16汽车起重机为对象,对其起升系统进行故障分析,建立相应的故障树。定性分析故障树从而得出故障树的最小割集,然后,又由故障树的仿真技术求出液压汽车起重机起升系统的可靠性指标,判定系统容易失效的部分,最后对系统的容易失效的部件进行分析,由得出的分析结果,提出相应的措施,进行改进。     

城市给水管网可靠性的故障树分析

对引起管网失效的各因素进行了分析,建立了给水管网失效的故障树,在此基础上,对故障树进行了定性和定量分析。     

基于灰色关联和故障树分析的航空齿轮箱故障诊断

航空齿轮箱是飞机运行的关键部件,为了对其进行故障诊断与预防,探究导致航空齿轮箱故障的关键因素,在故障树方法的基础上运用灰色关联分析对失效模式进行分析.结合现有数据对航空齿轮箱的故障树进行了定性分析与定量计算,理清了航空齿轮箱的结构特点与失效影响因素.借助灰色关联分析计算灰色关联度,找到系统薄弱环节,确定最小消耗下完成检修的故障诊断策略.     

某市政桥梁钢箱梁吊装系统风险评估与控制研究

采用指标体系法与故障树分析法对某市政桥梁钢箱梁吊装过程进行总体及专项风险评估,建立符合系统特征与建树规则的故障树,采用专家调查法确定各基本事件概率,并通过计算得到钢箱梁吊装系统顶事件失效概率及各基本事件对系统故障的关键重要度。将对系统失效概率影响较大的基本事件作为控制重点,给出合理的风险控制措施。     

挖掘机液压系统的故障树分析

建立挖掘同“铲半挖掘无呼的故障树”，定义了系统故障树最小割集矩阵和不交化最小集矩陈，利用微机辅助故障树分析软件对铲斗液压缸系统的可靠性进行了分析研究。     

住宅燃气系统故障树分析

针对住宅燃气系统建立了以住宅燃气系统失效为顶事件的失效故障树,分析了导致住宅燃气系统事故发生的各种可能因素,得到了故障数的各阶最小割集,并提出了相应的改进措施。     

基于系统思维的施工安全管理可靠性模型与实证分析

为提高施工安全管理水平,找出施工安全管理体系的失效原因,采用系统分析和模糊故障树方法对施工安全管理的可靠性进行研究。首先,基于系统思维,将施工安全管理作为一个系统,分解为安全组织、技术、资源、教育培训、逐级监管和应急管理六个子系统,依次梳理各子系统的管理要素,分析管理要素间的关系,构建各个子系统模型;然后针对所建立的子系统模型,以组织管理子系统为例,采用故障树方法分析组织管理子系统的失效原因,构建可靠性模型,分析其失效模式;最后,通过在武汉地区进行问卷调查对组织管理子系统的可靠性进行实证分析,得到组织管理子系统故障树中各底事件的关键重要度和发生问题的频率,识别出关键管理因素,并提出相应的改进措施。结果表明:施工安全管理可靠性模型有助于识别关键管理因素,从而有针对性地实行施工安全管理。     

旋挖钻机液压故障智能诊断系统研究

在故障树分析法的基础上,以奥盛特OTR旋挖钻机动力头系统为例,分析了该系统的故障机理和失效模式,建立了故障树,并编写了故障诊断规则库,确定了优选搜索策略,建立了完整的液压故障智能诊断系统.该诊断系统使用简单方便,性能可靠稳定,人机交互友好,大大提高了旋挖钻机液压故障诊断自动化与智能化水平.     

基于事件树的天然气管道风险定量分析

提出了以事件树分析为主线,结合故障树分析的城镇天然气管道风险定量分析方法：将管道泄漏分为渗透泄漏、穿孔泄漏和开裂泄漏3种泄漏模式;以管道泄漏为故障树分析的顶事件,分析管道泄漏的原因和概率;以管道泄漏为事件树分析的初因事件,分析管道泄漏在各种情况下造成的后果序列;以故障树分析事件树中后续事件的概率,以初因事件的概率和后续事件的概率计算后果事件的概率;分别对各个后果事件进行后果危害程度分析和经济损失估计;累加每个后果事件的经济损失数学期望,得到整个管道系统的风险值。     

Reliability of sprinkler system in Australian high rise office buildings

A comprehensive survey of sprinkler systems in high-rise office buildings was carried out to determine the reliability of various components of such systems in Australia. Based on the survey data, a fault tree analysis (FTA) has been used to estimate the overall reliability of these sprinkler systems. Data from 26 buildings were collected and are presented in this paper. In addition, data from overseas surveys has also been considered based on their relevance to the office buildings. The analyses are confined only to wet-pipe systems, as these constitute the vast majority of automatic sprinkler systems in Australia and New Zealand. To develop the fault trees, the designs found in usual practice are considered, rather than the designs just complying the Australian codes with the minimum requirements. A range of reliability for the sprinkler systems is estimated based on a number of considerations. Sprinkler zone shut off during tenancy changes and out of specification sprinkler head appear to be the main factors that may lead to a sprinkler system failure.     

Reliability of piping systems and effect of inspection methods

The reliability of a piping system (or a cylindrical vessel) is determined by a statistical failure process. The risk of failure at any period of service life is evaluated and the effects of various inspection methods on the total risk are examined. The influence of different parameters, such as quality control and relative detectable crack size, on the total reliability are studied.The results of this study point out that a program of periodic inspection at appropriate intervals may be as efficient as that of a continuous inspection. There is a definite advantage in detecting small relative flaw sizes in the initial periodic inspection. The interval between subsequent inspections can thus be increased.     

故障树分析法在城市燃气管道安全评价的应用

介绍了燃气管道安全评价技术的发展现状,对我国的燃气管道安全评价体系进行了分析。阐述了用于燃气管道安全评价的一些方法,论述了故障树分析法的应用。根据燃气管道事故归纳了泄漏影响因素,对不同的故障树模型进行描述,提出了以故障树分析法为主的定性、定量安全评价工作程序,提出了改进的建议。     

Evaluation of building performance using fuzzy FTA

Estimating exact probabilities of occurrence of fault events for use in the conventional fault tree analysis (FTA) is difficult when failure data are insufficient or fault events are imprecise such as human error. A hybrid approach employing fuzzy sets and possibility theory is proposed to overcome this problem. In this approach, failure possibilities of vague events are characterised by fuzzy sets to translate expert subjective judgements while fuzzy fault rates are derived from fuzzy possibility scores based on a transformed Onisawa's possibility function. An example of beam failure illustrates the use of the approach and demonstrates the capability of the model that can assist safety engineers to effectively assess fault possibilities and better evaluate building performance.     

建设工程质量监管的机制失灵与制度补救——以上海“莲花河畔景苑”楼房整体倾覆案为视角

工程质量事故频频发生的根本原因在于政府工程质量监管机制失灵。政府工程质量监管机制失灵的原因又在于,核准制改为备案制进一步刺激"经济人"的逐利性,事后监管助长政府对工程质量的形成过程不作为,行业陋规加剧工程建设资金实际投入不足,业主在建设工程质量验收过程中严重缺位。应当恢复核准制度,加强政府的工程质量监管责任,严格市场准入门槛,严格规范工程合同行为,支持业主的房屋验收权利,积极发展房屋验收中介机构,以充分发挥建设工程质量监管机制的效用。     

钢板笼混凝土短柱轴压性能试验研究

钢板笼混凝土(Prefabricated Cage System,PCS)是一种新型的混凝土结构,有着施工速度快、施工质量容易控制、延性好和耗能能力强等优点,可以广泛应用于混凝土结构的各种构件中,是混凝土结构体系的一个重要补充。通过对4根不同特征值的钢板笼混凝土短柱和1根钢筋混凝土短柱进行轴压试验研究,得出:钢板笼混凝土柱的轴压破坏特征与钢筋混凝土柱基本相同;钢板笼混凝土柱的延性要优于钢筋混凝土柱,在箍筋断裂时延性提高最大可达49.2%;钢板笼混凝土柱的耗能比钢筋混凝土柱好,耗能可以提高73.5%;钢板笼混凝土中纵筋受力与其配置位置有关。     

A fuzzy logic approach to model delays in construction projects using rotational fuzzy fault tree models

Delays in construction projects are inevitable and, as a result, claims and disputes arise. Different causes of delay can come into play and therefore the need to identify and classify different causes of project delay arises. Different factors that contribute to project delay affect the likelihood of project delay in different degree of effectiveness. Fuzzy fault tree analysis (FTA) is suggested by this research to estimate the likelihood of project delay. Likelihood of delay membership function is further quantified using the weighted average defuzzification method. Two fuzzy logic models are implemented into the fuzzy FTA, using Visual Basic software: the models discussed in this research are Baldwin's rotational model and the Angular model. Comparison between the two fuzzy logic models has been carried out. Validation of the fuzzy FTA computer model is performed. Validation of the model was performed for adequacy and applicability of the model. On average, the validation performed by independent construction engineers and fuzzy logic experts produced satisfactory results. The computer software suggested by this study is an attempt to assess the likelihood of the project delay, which helps reduce delays in construction projects that can cause time loss.     

基于WBS的机场测绘工程项目管理

以西南某机场测绘工程为例,在精度要求是一般工程项目5倍的情况下,基于WBS工程项目管理方法,通过剖析测绘工程进度计划的制约因素和质量管理关键因素,优化测绘工程项目中进度与质量控制的关键切入点,找出测绘工程项目的作业流程中存在的障碍,并建立进度和质量管理体系。同时,针对具体实践中流程障碍的分析与研究,提出了具体的优化对策。旨在更好地为大中型综合测绘工程项目在进度控制和质量管理方面提供合理意见,建立的管理体系在工程实践中得到了应用,并取得了良好的效果。     

环境室涡轮制冷机工作可靠性影响因素分析

采用故障树分析法,对环境室空气制冷系统涡轮制冷机工作可靠性的影响因素和相互关系作了分析.指出影响涡轮工作可靠性的外部直接因素有轴承供气压力过低、涡轮超转、供气含湿量过大、供气压力急剧波动、供气洁净度和外界冲击.对影响直接因素的一些间接因素进行了分析,探讨了提高涡轮制冷机工作可靠性的一些措施和一些可靠性影响参数的控制范围.