舰船损管系统生命力评估

建立了舰船损管系统生命力评估构架，解决了诸如水消防系统这样遍布全舰且元件之间逻辑关系十分复杂的系统损伤概率计算方法，直接使用损伤比例进行综合加权计算，为舰船损管系统设计提供了评估方法．     

基于模糊故障树方法对装备结构改进评估的应用

针对现代高机动、大型雷达结构系统的复杂和故障特征及原因具有模糊性的特点,应用模糊故障树的方法、原则及步骤,对某型装备的结构故障概率运用模糊数学的相关理论进行定量分析,验证相应改进方向的针对性,找到一套评估改进效果的可行方法。     

基于模糊故障树的公铁交叉项目施工安全风险分析

由于穿越工程箱涵顶进施工难度大、技术复杂一旦发生安全事故将会造成重大的损失,据此提出WBS—RBSS分解结构结合故障树分析方法对顶进施工安全事故的风险因素进行全面辨识,采用三角模糊数描述基本事件的模糊概率,求得穿越工程箱涵顶进施工过程中发生安全事故的模糊概率。为此类工程的安拿凰险岔析提供了一种科学的方法。     

基于故障树的计算机安全性分析模型

提出了通过分析计算机系统的资源实体、访问者权限、安全需求和弱点等安全属性,按照不同的安全需求构造出安全故障树来直观地反映攻击者可能选取的攻击手段的安全状况评价方法;分析安全故障树,使用潜在攻击路径和系统安全失效概率从定性和定量两个方面表达计算机系统的安全状况,为系统的安全改进提供指导和建议。     

舰船推进轴系设计方案的综合评估

探讨了将多目标决策理论应用于舰船推进轴系设计方案综合评估的方法，建立了推进轴系设计方案的多层次评估模型，讨论了基于层次分析法评估以值确定的矢量计算方法，给出了运用模糊隶属函数的底层典型定量指标的确定方法，文中论述的方法对舰船推进轴系设计方案的科学评估决策具有实用价值。     

舰船冲击运动引起人员损伤评估方法研究综述

水下爆炸在极短的时间内产生巨大的冲击加速度,引起舰船上人员严重损伤,大大降低人员的作业能力.对人体冲击损伤程度的评估是评价舰船作业能力的重要依据.由于人群的广泛差异性,导致人体对冲击的耐受能力具有广泛差异性,不同的个体发生特定类型的损伤时的阈值水平也是不同的.总结了在舰船冲击损伤研究领域经常使用的各种人体冲击损伤评估方法,并提出了评估整个人体冲击损伤程度的流程.目前在使用这些评估方法在进行冲击损伤预测时需要专家的指导和参与,确定适当的个体或环境参数.对于每一个具体问题,最好采用多个耐受性标准和评估方法进行交叉引用或前后对照,才能得到比较可靠的评估结果.     

战斗部外爆对舰船毁伤快速评估算法

为对舰船在战斗部外爆时破片和冲击波的毁伤进行快速评估,建立快速仿真算法。通过分析目标各部件和战斗部起爆点的相对位置关系,结合经验公式,计算舰船在战斗部外爆加载时的超压分布。模拟仿真战斗部外爆时的破片场,使用射击线方法,计算破片对舰船的侵彻毁伤。使用C++和glut库,实现仿真场景的三维漫游,给出有关的毁伤图像。     

应用Petri网改进基于故障树的诊断方法

故障树是表示故障发生和故障传播关系的一种逻辑模型,基于故障树诊断方法的广泛应用由于实际故障树分析过程的ＮＰ困难问题而受到妨碍。而Ｐｅｔｉｒ网是一种特殊的有向网,适合于描述故障的传播关系。本文提出了两种基于Ｐｅｔｒｉ网的改进方法,与下行法相比,用该方法寻找最小割集和最小路集能有效地节省上计算时间,提高推理速度和效率;最后还应用Ｐｉｔｒｉ网的状态方程分析方法提出了基于Ｐｅｔｒｉ网的故障监测和诊断方法。     

抗冲击瓦结构舰船毁伤效能评估研究

针对舰船毁伤效能评估问题,进行了抗冲击瓦结构舰船毁伤效能评估方法研究。研究结果显示,炸药爆炸威力及目标易损性构成了不可偏废型舰船毁伤效能评价指标体系,爆炸威力赋值可通过炸药TNT当量及舰船排水量计算得出,抗冲击瓦抗毁伤性能评估值可采用灰色层次分析法计算,采用文中给出的毁伤效能计算方法能够实现抗冲击瓦结构舰船毁伤效能的量化评估。     

抗冲击瓦结构舰船毁伤效能评估研究

针对舰船毁伤效能评估问题,进行了抗冲击瓦结构舰船毁伤效能评估方法研究。研究结果显示,炸药爆炸威力及目标易损性构成了不可偏废型舰船毁伤效能评价指标体系,爆炸威力赋值可通过炸药TNT当量及舰船排水量计算得出,抗冲击瓦抗毁伤性能评估值可采用灰色层次分析法计算,采用文中给出的毁伤效能计算方法能够实现抗冲击瓦结构舰船毁伤效能的量化评估。     

基于装备损伤概率的舰艇动力系统安全性分析

考虑舰艇损害管制过程中人员因素对系统的影响，运用马尔科夫链对人员操作引起的舰艇动力系统损伤概率进行修正，根据修正后的毁伤概率，建立概率危险性评估模型，引入危险度指标，对动力系统在遭受武器攻击情况下的危险度进行了计算，并依据计算结果对系统安全度进行评定。     

基于贝叶斯网络的核电站应急电力系统安全评价

在故障树分析法(FTA)基础上提出了一种基于贝叶斯网络(BN)的核电站应急电力系统安全评价方法,比较了FTA和BN在建立安全评价模型和评价能力上的不同.该方法在应对众多影响因素上有很大优势,能进行更多有意义的分析:既能进行前向的预测推理,又能进行后向的诊断推理,可以找出影响故障的组合模式,从而能够找出系统的薄弱环节.同时采用基于Matlab的BNT软件包,大大简化了计算过程.通过对10MW高温气冷堆(HTR-10)应急电力系统的安全评价实例的分析,证明该方法是对传统的基于故障树分析的安全评价方法的有益改进.     

Introducing a heuristic approach to enhance the reliability of system safety assessment

Probabilistic risk assessment techniques are the important tools which can considerably improve the safety performance of the studied system and reduce the risk to an acceptable level. Typically, decision‐making process is an important part of risk assessment methods that accordingly bring the ambiguity inside. Decision makers as experts commonly express their subjective opinions about the occurrence of the root events in order to obtain the probability of the undesired event. Subsequently, the critical root events are identified, and possible intervention is performed to reduce the probability of the critical events. However, the serious point is the viability of the obtained probabilities and priority ranking of the critical events. In this study, a heuristic optimization model of linear mathematical programming using triangular intuitionistic fuzzy number (TrIFN) is proposed to obtain the feasible, optimum, and reliable results compared with available methods. The Spearman correlation is performed to examine the reliability and behavior of the proposed model. In order to show the effectiveness of the proposed approach, it is applied on a real case study. The application of the model confirms its robustness to prioritize critical root events over the conventional one.     

计算机辅助事故树绘图研究

实现计算机辅助事故树绘图是计算机辅助事故树绘图是计算机辅助事故树分析中的重要组成部分。本文给出了两种实用的计算机辅助事故绘图方法,即“堆砖法”和“控制点法”。而后者由于真正实现了交互式绘图,解决了事故数据的自动采集和处理,因而实际上也是事故树的一种数据输入法,即由图形得到事故树全部数据的图形输入法。文中对这两种方法的算法进行了详细描述,这两种思想和算法不仅解决了事故树的实际绘制问题,而且对绘制其它类型的树及图将大有益处。     

大型舰艇系统破损失效概率计算

对于大型舰船，多次命中和结构防护成为破损失效概率计算的主要问题，该文通过对各种算法的比较和研究，综合了逻辑代数法、网格积分法和蒙特卡罗随机模拟法的优点，较好地解决了这些问题，得到了满意的计算结果。     

基于梯形模糊数的数控磨床砂轮架系统故障树分析

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。     

Dynamic fault tree analysis using Monte Carlo simulation in probabilistic safety assessment

Traditional fault tree (FT) analysis is widely used for reliability and safety assessment of complex and critical engineering systems. The behavior of components of complex systems and their interactions such as sequence- and functional-dependent failures, spares and dynamic redundancy management, and priority of failure events cannot be adequately captured by traditional FTs. Dynamic fault tree (DFT) extend traditional FT by defining additional gates called dynamic gates to model these complex interactions. Markov models are used in solving dynamic gates. However, state space becomes too large for calculation with Markov models when the number of gate inputs increases. In addition, Markov model is applicable for only exponential failure and repair distributions. Modeling test and maintenance information on spare components is also very difficult. To address these difficulties, Monte Carlo simulation-based approach is used in this work to solve dynamic gates. The approach is first applied to a problem available in the literature which is having non-repairable components. The obtained results are in good agreement with those in literature. The approach is later applied to a simplified scheme of electrical power supply system of nuclear power plant (NPP), which is a complex repairable system having tested and maintained spares. The results obtained using this approach are in good agreement with those obtained using analytical approach. In addition to point estimates of reliability measures, failure time, and repair time distributions are also obtained from simulation. Finally a case study on reactor regulation system (RRS) of NPP is carried out to demonstrate the application of simulation-based DFT approach to large-scale problems.     

救捞工程中的多指标决策方法探讨

建立了基于综合权重的双基点多指标决策模型。分别从主观和客观两个方面来分析评估指标的权重,迭加得到综合权重,并利用它进行相对贴近度分析,从而判断方案的优劣,得到最佳方案,使问题的优化与决策更加科学、合理。以拖带方案的优化决策分析为例,验证了多指标决策模型的可行性,简述了它在救捞工程中的应用方法。     

An engineering approach to safety assessment for non-J-controlled crack growth

The -integral has been proposed as a new fracture parameter for non-J-controlled crack growth in previous studies. In this paper, the -integral is investigated to assess the safety of structures with defects. The estimation formula for the -integral is presented to calculate the crack driving force by referring to the engineering estimation expression of the J-integral. The material resistance curves J_R−Δa and , of A533B material, are obtained by tests and nonlinear finite element analyses. The -integral failure criterion for non-J-controlled crack growth is assumed in the paper according to the crack driving force and the material resistance curves. The method of admissible stress curve, i.e. the stress-crack length curve, is developed to simplify the conventional engineering assessment procedure by following the failure criterion for non-J-controlled crack growth. A new engineering safety assessment approach is proposed to assess the ductile fracture instability of flawed structures for non-J-controlled crack growth by the method of an admissible stress curve. Two examples for the compact tension configuration and the cylinder with a surface crack under internal pressure are examined by using the new engineering assessment approach. The new engineering safety assessment approach obviously simplifies the conventional engineering assessment procedure. By comparing with the tests, the results from these two examples show that this new engineering safety assessment approach for non-J-controlled crack growth gives a reliable prediction for the ultimate load capacity of flawed structures.     

Development of measures to estimate truncation error in fault tree analysis

The fault tree quantification uncertainty from the truncation error has been of great concern for the reliability evaluation of large fault trees in the probabilistic safety analysis (PSA) of nuclear plants. The truncation limit is used to truncate cut sets of the gates when quantifying the fault trees. This paper presents measures to estimate the probability of the truncated cut sets, that is, the amount of truncation error. The functions to calculate the measures are programmed into the new fault tree quantifier FTREX (Fault Tree Reliability Evaluation eXpert) and a Benchmark test was performed to demonstrate the efficiency of the measures.The measures presented in this study are calculated by a single quantification of the fault tree with the assigned truncation limit. As demonstrated in the Benchmark test, lower bound of truncated probability (LBTP) and approximate truncation probability (ATP) are efficient estimators of the truncated probability. The truncation limit could be determined or validated by suppressing the measures to be less than the assigned upper limit. The truncation limit should be lowered until the truncation error is less than the assigned upper limit. Thus, the measures could be used as an acceptability of the fault tree quantification results. Furthermore, the developed measures are easily implemented into the existing fault tree solvers by adding a few subroutines to the source code.