基于动态故障树铸造起重机起升机构重要度分析

铸造起重机起升机构包括多套起升机构、制动机构，传统故障树无法准确描述其失效机理，传统重要度分析不能准确反映各底事件的真实重要度。通过基于动态故障树的重要度分析，对起升机构的工作特点、结构组成进行重要度分析，得到铸造起重机起升机构的薄弱环节，为提高铸造起重机可靠性和安全性提供理论支撑。     

基于模糊故障树和蒙特卡洛方法的智能铲运系统可靠性分析

为了分析智能铲运系统在三山岛矿区内实际运行使用的可靠性，提出将模糊故障树分析与蒙特卡洛仿真相结合的研究方法。以智能铲运系统运行使用故障为顶事件，确定了16个中间事件和33个底事件，并构建了故障树模型。采用模糊集合理论的方法，通过10位专家的结果反馈，求取了各底事件的发生概率，进而对故障树进行了定量分析，得到顶事件发生概率为0.3481%。基于建立的故障树模型，采用蒙特卡洛仿真模拟的方法，编写蒙特卡洛仿真算法，合理设置仿真参数，最后得到了平均无故障时间、可靠性与不可靠性曲线以及系统失效概率曲线。通过对底事件的仿真重要度进行计算，结果表明：操作规范不合格（管理原因）和信息沟通失误（人员原因）对系统可靠性影响最大，影响最大的机械原因为操作装置故障和制动系统老化。通过将计算结果与实际数据进行对比分析，验证了该方法的准确性和有效性。     

曲柄连杆机构中十字头与活塞杆连接结构分析与改进设计

分析曲柄连杆机构中十字头与活塞杆原有结构存在的问题,提出新型连接方式设计方案,对连接件进行有限元分析,保证了零件强度要求与连接结构的可靠性,进而提高了机械设备的连续运转率和工作效率。     

平面连杆机构等效转动惯量的计算及应用

根据单自由度平面连杆机构的等效动力学模型,以功能原理为基础,建立平面连杆机构等效转动惯量的解析计算公式。应用Inventor建立曲柄飞剪剪刀体模型来计算摇杆对其回转中心的转动惯量以及连杆对其质心的转动惯量,然后根据上述建立的平面连杆机构等效转动惯量的解析计算公式来求解曲柄飞剪剪刀体部分对电机轴的等效转动惯量,从而为曲柄飞剪电机的选择提供一定的参考。     

铸坯毛刺去不净FreeFta软件故障树分析法

根据首秦铸坯毛刺去不净故障状态,从锤式去毛刺法机理分析了锤刀的离心惯性力、毛刺被剪切面与钢坯的夹角、刀具作用点与钢坯的距离等对毛刺去不净的影响因素。通过FreeFta故障树分析软件,结合去毛刺机实际维护经验,绘制了毛刺去不净故障的故障树,并计算出顶上事件发生的概率和基本事件的重要度,分析出整个去毛刺机系统的薄弱环节,有效指导了去毛刺机的故障诊断与维护使用。     

有限元分析在曲柄摇杆式飞剪机架强度评估中的应用

为掌握某曲柄摇杆式飞剪机架强度及变形情况,采用理论分析的方法计算了剪切系统各铰接点的受力大小,在此基础上建立了该飞剪机架的有限元模型,并进行了仿真分析。结果表明机架在下刀架的支承处是机架薄弱环节,机架强度及变形均在安全范围内。     

层次分析法在焦炉四大车系统可靠性分析中的应用

应用故障树分析法建立自动定位系统故障树模型,并进行定性分析。利用层次分析法分析专家数据,对该系统进行定量分析,分析结果能帮助分析焦炉四大车系统的薄弱环节,为系统的深入开发、维护提供了重要的参考。     

并网型风电机组可靠性设计

介绍了并网型风电机组可靠性指标及其评估方法,及并网型风电机组的运行情况;根据并网型风电机组可靠性串联模型,对并网型风电机组进行可靠性设计,找出其薄弱环节,提高其可靠性,达到提高可利用率和年发电量的目的.     

曲柄连杆板带飞剪装置传动模式优化方法

文章以曲柄连杆板带飞剪装置传动系统为研究对象,求解曲柄连杆机构受力关系并计算飞剪齿轮箱在工作过程承受的剪切扭矩,定量讨论在单飞轮以及双飞轮两种模式下飞剪传动系统的功率流分配关系,进而量化在两种设计模式下飞剪齿轮箱的承载能力。工程实例表明:在大规格板带飞剪装置中,双飞轮模式可以减小单个飞轮质量的同时确保飞剪装置具有更高的可靠性。     

高炉炉顶液压系统的设计及故障树分析

以承德钢铁公司炼铁厂450m3高炉炼铁炉顶液压系统为实际依据,通过分析高炉炉顶设备的组成部件及工艺原理,设计出高炉炉顶液压系统,并介绍了液压系统工作原理。以故障树作为故障分析方法,建立了以大钟液压缸出现故障为顶事件的故障树,并对该故障树进行了定性、定量分析,从而对液压元件的可靠度在理论上有了一定的把握,为提高液压系统整体可靠性提供了重要依据。     

Probability-Based Bridge Network Performance Evaluation

This paper presents a comprehensive mathematical model for evaluating the overall performance of a bridge network based on probability analyses of network connectivity, user satisfaction, and structural reliability of the critical bridges in the network. A bridge network consists of all nodes of interest in a geographical region. These nodes of interest are connected to each other through multiple paths. The network performance evaluation in terms of connectivity is formulated by using an event tree technique. The network performance measure of user satisfaction deals with traffic demand and capacity of each link in the network. Moreover, the shortest paths in terms of total traffic costs are identified by network optimization algorithms for each pair of the origin and destination nodes of interest under the specified traffic demands. Using this information, the minimum-weight spanning tree (MST) that consists of the identified shortest paths is constructed. The bridges associated with MST are defined as the critical bridges in the network. The network performance in terms of structural reliability of the critical bridges can be computed from system reliabilities of the critical bridges by using a series-parallel system model. Finally, by combining the above three criteria, a single numerical measure is proposed to evaluate the overall performance of the bridge network. This novel approach is illustrated on a group of fourteen existing bridges with different reliability profiles located in Colorado. This study provides the basis of a network-level bridge management system where lifetime reliability and life-cycle costs are the key considerations for optimal bridge maintenance strategies.     

金属矿山矿井通风监控系统事故树分析

运用事故树分析法(FTA)对金属矿山矿井通风监控系统进行故障分析,建立事故树模型;对事故树定性分析,求出最小割集、最小径集和各基本事件的结构重要度,利用最小径集分析预防事故发生的途径和应采取的对策措施;通过顶事件的发生概率以及各基本事件的临界重要度计算对事故树进行定量分析,得出病毒感染、人的责任心不强、维修技术差等因素最有可能导致系统故障。基于定性与定量分析的结果,从系统安全、设备可靠、管理到位3方面提出对策措施,保障金属矿山矿井通风监控系统正常运转。     

矿井通风系统可靠性数值分析

按照矿井通风构筑物分为截断风流的构筑物、通过风流的构筑物和调节风流的构筑物三类的分类方法,给出了各类通风构筑物、扇风机单元和分支可靠度的计算方法.运用不交型布尔代数,给出了矿井通风网络可靠度的计算方法.研究了矿井通风系统可靠度优化分配的非线性规划模型,提出矿井通风网络平衡方程组的Jacobi行列式J的绝对值大小,体现了系统可靠度的高低.着重研究了各分支风量一定时,调节各分支的风阻,使J最大化的优化模型.并以例题验证部分结果.     

Bayesian Network Enhanced with Structural Reliability Methods: Application

The enhanced Bayesian network (eBN) methodology described in the companion paper facilitates the assessment of reliability and risk of engineering systems when information about the system evolves in time. We present the application of the eBN: (1) to the assessment of the life-cycle reliability of a structural system; (2) to the optimization of a decision on performing measurements in that structural system; and (3) to the risk assessment of an infrastructure system subject to natural hazards and deterioration of constituent structures. In all applications, observations of system performances or the hazards are made at various points in time and the eBN efficiently includes these observations in the analysis to provide an updated probabilistic model of the system at all times.     

非煤矿山井下通风监测监控系统分析

使用事故树对非煤矿山井下通风监控系统进行分析,建立事故树模型。事故树定性分析求出最小割集、最小径集和各基本事件的结构重要度,并利用最小径集分析预防事故发生的途径和应采取的对策措施。对顶事件的发生概率以及各基本事件的临界重要度计算,得出病毒感染、人的责任心不强、维修技术差等因素最有可能导致系统故障。基于定性、定量分析的结果,为保障系统正常运转,从系统安全、设备可靠、管理到位三方面提出对策措施。     

Diagnosing Upsets in Anaerobic Wastewater Treatment Using Bayesian Belief Networks

Bayesian belief networks are probabilistic knowledge-based expert systems that predict the probability of an event occurring or diagnose the most probable causes of specific problems. Although Bayesian belief networks calculate the probabilities of events both before and after the introduction of evidence and are particularly useful for complicated systems with nonlinear relationships between causes and effects, they have not been widely applied to wastewater treatment systems. A Bayesian belief network for diagnosing upsets in an anaerobic wastewater treatment system was developed using the anaerobic sequencing batch reactor as a model system. A new approach for determining the conditional probabilities of the states of the variables was developed using a microbial kinetics model in conjunction with Monte Carlo simulation. The completed network suggests the most probable cause of upsets to the anaerobic sequencing batch reactor and updates its suggestions as more evidence is provided. The approach used is general and may be applied to other anaerobic treatment systems.     

矿井通风系统可靠性量化分析

矿井通风系统是矿山生产的重要系统之一,对其进行可靠性分析具有现实意义。从主要通风机系统和通风网络两部分对矿井通风系统进行了可靠性量化分析。鉴于主要通风机系统的冷储备可修特性,应用Markov过程理论,建立矿井主要通风机的可靠性量化模型;在各风路可靠性的基础上结合网络流理论知识运用"布尔代数"、"删去留下"等方法建立矿井通风网络可靠性量化模型。最后,基于"串联网路",建立了矿井通风系统可靠性量化模型,并经实例验证其可行性。     

削壁充填采矿法采场安全管理体系可靠性分析

夹皮沟矿业公司各矿区多为急倾斜极薄矿脉,采矿方法以削壁充填采矿法为主。由于安全事故多发于采场,将采场安全管理作为矿山安全生产的落脚点,为此建立了采场安全管理体系。这一管理体系的可靠程度如何,可以运用事件树分析法进行分析,其分析结果不仅可以说明管理体系的可靠性,还可以作为管理体系进一步改进完善的依据。通过分析,夹皮沟矿业公司采场安全管理体系具有较高的可靠性。     

Reliability Evaluation of Earth Slopes

The reliability analysis of earth slopes is considered. For slope safety assessment, the first-order reliability method is employed for estimating the probability of failure or reliability index. Since the failure of any slip surfaces implies failure of the slope, the slope is considered as a series system. The system aspect of the slope in the reliability analysis is dealt with by defining a limit state of the system as a function of the minimum of the ratio of the shear strength to the mobilized shear strength for each of all potential slip surfaces. Such a ratio for a given slip surface is evaluated using the extended generalized method of slices. The reliability analysis procedure described is applied to example slopes to illustrate the impact of the probability distribution type, and the spatial variability of the soil properties on the probability of failure of the slopes.     

通讯数据的可靠性分析

利用概率论中的二项式分布和中心极限定理等理论 ,对通讯系统的可靠性作了较为详细的定量分析 ,并对报文长短的截取作了优化设计 .此种方法已应用于某热轧厂运输链通讯系统的可靠性分析 .