指数型设备多台同步可靠性增长的数据分析

关于同一环境应力下指数型设备的单台可靠性增长试验，文中对前人的数据分析方法提出了两点改进，克服了原有方法分析结果往往偏差较大，以及在非故障结尾情况，最后的无故障时间长短对分析结果影响较大的缺点；此外，导出了失效率置信密度的精确计算公式，以替代原来的近似公式。还研究了多台同步试验的数据分析方法，最后进行了模拟研究。     

软件测试数据的统计分析

软件可靠性评估是软件可靠性研究的重要问题,本文研究了软件测试数据的样本点序法,获得了软件可靠度的置信下限,证明了该置信限的最优性。最后给出一个实例说明该方法的可行性。     

An Accessible Way to Establish Reliability and Expected Time‐to‐Failure for Cold Standby Redundant Systems Subject to Periodic Inspections

Cold standby systems subject to periodic inspections are widely applied in industry. However, the establishment of system reliability, expected time to failure, and appropriate time interval between inspections in a form accessible to industrial and maintenance engineers are still challenging issues. This paper aims to develop equations that solve this problem based on an analysis of expected exposure time for active and redundant components. A table and a general analytic expression along with graphs were elaborated to allow for the establishment of the appropriate time interval between inspections, given the level of reliability required and the number of standbys available. The main advantage of the results presented in this paper is the ability to conduct the reliability evaluation without the use of complex formulations such as Markov process or Laplace transforms that are usually beyond the skills of the industrial and maintenance staff. Also, a comparison with the exact solution using probability theory is presented, and it is proved that the method developed in this study provides a good approximation for practical applications. Copyright © 2015 John Wiley & Sons, Ltd.     

Holistic reliability analysis of weighted voting systems from a multi-state perspective

The computation of the reliability of weighted voting systems is an important problem in reliability theory due to its potential application in security, target identification, safety and monitoring areas. Voting systems are used in a wide variety of applications where an acceptance or rejection decision has to be made about a binary proposition presented to the system. For these systems, it is of interest to obtain the probability so that based on the vote of decision-making units, the system aggregates these votes into the right decision when presented with such a proposition. This paper presents a holistic work on weighted voting system reliability by presenting modeling, computation, estimation and optimization techniques. The modeling part takes advantage of the structure of weighted voting systems to present a model of its reliability as a multi-state system. Next, based on the multi-state view of the system, an exact computational approach based on multi-state minimal cut and path vectors is introduced. The paper then acknowledges the computational complexity of the problem and provides a Monte Carlo simulation approach that estimates system reliability accurately and in an efficient computational time. Finally, an optimization heuristic that generates quasi-optimal solutions is presented that is able to solve the problem of maximizing the reliability of a weighted voting system based on a specified number of decision-making units with known reliability characteristics.     

Fast approximate methods for the reliability analysis of computer networks

The complexity of computer communication networks has taken a dramatic upswing, following significant developments in electronic technology such as medium and large scale integrated circuits and microprocessors. Although components of a computer communication network are broadly classified into software, hardware and communications, the most important problem is that of ensuring the reliable flow of information from source to destination. An important parameter in the analysis of these networks is to find the probability of obtaining a situation in which each node in the network communicates with all other remaining communication centres (nodes). This probability, termed as overall reliability, can be determined using the concept of spanning trees. As the exact reliability evaluation becomes unmanageable even for a reasonable sized system, we present an approximate technique using clustering methods. It has been shown that when component reliability ⩾ 0.9, the suggested technique gives results quite close to those obtained by exact methods with an enormous saving in computation time and memory usage. For still quicker reliability analysis while designing the topological configuration of real-time computer systems, an empirical form of the reliability index is proposed which serves as a fairly good indicator of overall reliability and can be easily incorporated in a design procedure, such as local search, to design maximally reliable computer communication network.     

A novel framework for the reliability modelling of repairable multistate complex mechanical systems considering propagation relationships

Due to the propagation, amplification, and concatenation in a failure process, the reliabilities of repairable multistate complex mechanical systems (RMCMSs) may be affected by a significant fluctuation due to a small exception associated with a reliability indicator. Focused on the problems arising from the lack of propagation relationships among fault modes, functional components, and failure causes in conventional reliability models, a novel framework for reliability modelling is proposed to comprehensively analyse the reliabilities of RMCMSs. First, the reliability models are abstracted as weighted and directed networks with five layers. Second, an improved failure mode and effects analysis (IFMEA) method combined with the D‐number method and VIKOR approach is presented to determine the importance of reliability nodes. Third, a cut set of the reliability model is generated by any exception of a reliability indicator by considering the propagation relationships, and the reliability sensibility index is defined to characterize the fluctuations in system reliability. The effectiveness of the proposed framework is demonstrated in an actual reliability modelling application. As an intuitive method, the proposed framework inherits the advantages of conventional models but overcomes the drawbacks of these existing methods. Therefore, this method can be flexibly and efficiently used in the reliability modelling of RMCMSs. Moreover, the approach provides a foundation for comprehensive and dynamic reliability analysis and the failure mechanism mining of RMCMSs, and it can be used in other engineering applications.     

A new reliability analysis method for repairable systems with multifunction modes based on goal‐oriented methodology

This paper proposes a new systematic reliability analysis method for repairable systems with multifunction modes based on the goal‐oriented (GO) method. First, we create a new function GO operator, a new logical GO operator, and a new auxiliary GO operator, deduce their GO operation formulas, and propose some new rules of the GO operation and an exact algorithm with shared signal of the GO method for such systems. Then, we formulate the analysis process of repairable systems with multifunction modes based on the new GO method. Finally, we apply this new GO methodology to reliability analysis of the control system for a heavy vehicle. To verify the feasibility, advantage, and reasonableness of the new GO methodology, we compare its analysis results with those of fault tree analysis and Monte Carlo simulation. We show that the proposed GO method has clear advantages in system reliability modeling and analysis. All in all, this study not only improves the theory of the GO method and widens its application but also provides a new approach for conducting reliability analysis of complex systems quickly and efficiently.     

An evaluation of the multi-state node networks reliability using the traditional binary-state networks reliability algorithm

A system where the components and system itself are allowed to have a number of performance levels is called the Multi-state system (MSS). A multi-state node network (MNN) is a generalization of the MSS without satisfying the flow conservation law. Evaluating the MNN reliability arises at the design and exploitation stage of many types of technical systems. Up to now, the known existing methods can only evaluate a special MNN reliability called the multi-state node acyclic network (MNAN) in which no cyclic is allowed. However, no method exists for evaluating the general MNN reliability. The main purpose of this article is to show first that each MNN reliability can be solved using any the traditional binary-state networks (TBSN) reliability algorithm with a special code for the state probability. A simple heuristic SDP algorithm based on minimal cuts (MC) for estimating the MNN reliability is presented as an example to show how the TBSN reliability algorithm is revised to solve the MNN reliability problem. To the author's knowledge, this study is the first to discuss the relationships between MNN and TBSN and also the first to present methods to solve the exact and approximated MNN reliability. One example is illustrated to show how the exact MNN reliability is obtained using the proposed algorithm.     

不完全概率信息的车辆常用弹簧的可靠性灵敏度设计

将可靠性设计理论与灵敏度分析方法相结合，讨论了车辆常用弹簧的可靠性灵敏度设计问题，提出了可靠性灵敏度设计的计算方法，给出了可靠性灵敏度的变化规律，研究了设计参数的改变对车辆常用弹簧可靠性的影响，为车辆常用弹簧的可靠性设计提供了理论依据。     

Error bounds for the reliability index in finite element reliability analysis

This work presents an extension of the goal‐oriented error estimation techniques to the reliability analysis of a linear elastic structure. We use a first‐order reliability method in conjunction with a finite element analysis (FEA) to compute the failure probability of the structure. In such a situation the output of interest that is computed from the FEA is the reliability index β. The accuracy of this output, and thus of the reliability analysis, depends, in particular, on the accuracy of the FEA. In this paper, upper and lower bounds of the reliability index are proposed, as well as simple bounds of the failure probability. An application to linear fracture mechanics is presented. Copyright © 2011 John Wiley & Sons, Ltd.     

Hybrid reliability analysis with uncertain statistical variables,sparse variables and interval variables

There are differences among sampling data and representation types of uncertain statistical variables, sparse variables and interval variables, which increase the complexity of structure reliability analysis. Therefore, a hybrid first order reliability analysis method considering the three types of uncertain variables is demonstrated in this article. First, distribution types and distribution parameters of sparse variables are identified and probabilistically estimated. Secondly, interval variables are transformed into probabilistic types using a uniformity approach. Thirdly, a unified hybrid reliability calculation method considering these uncertain variables simultaneously is demonstrated. The most probable point (MPP) is searched for using the first order reliability method, and then a linear approximation function of performance function is constructed in the neighbourhood of the MPP. Finally, the belief and plausibility measures of the reliability index are efficiently calculated using the theoretical analytical method. Three examples are investigated to demonstrate the effectiveness of the proposed method.     

Reliability analysis against progressive failure of TLP tethers in extreme tension

The tension leg platform (TLP) is a moored floating structure whose buoyancy is more than its weight. The mooring system of TLP consists of number of tensioned tethers connected to the columns at the top and anchored to the seabed at the bottom. These tethers are vulnerable to failure due to extreme (maximum and minimum) tensions. The reliability study of these tethers is an important subject of study. The reliability may further deteriorate after the failure or removal of any of these tethers. In the present study, reliability analysis of an intact TLP and TLP with one tether missing has been carried out. A Von-Mises failure criterion has been adopted to define the failure of tether against maximum tension. The minimum tension failure occurs when the tethers slack due to loss of tension. The limit state functions for maximum and minimum tension cases have been derived. The computationally efficient algorithm First order reliability method (FORM) has been adopted for reliability calculations. Results are presented in terms of reliability indices and probabilities of failure for each sea state. The probabilities of failure so obtained for different sea states have been used for the assessment of annual and life time probability of failures. Reliability of the TLP with one tether missing has been compared with that of the corresponding intact TLP. Effect of wind has also been studied on the progressive failure of TLP tethers and the results have been compared with that of an intact TLP.     

压杆稳定的非概率可靠性凸集合模型分析方法

 针对概率可靠性模型对原始数据要求高的局限性,用凸集合模型来描述影响压杆稳定可靠性分析中的不确定参数,利用一阶Taylor展开式基于凸集合模型讨论了压杆稳定分析中不确定性参数对压杆稳定响应的影响,提出了压杆稳定的非概率可靠性度量的指标.此方法对数据的要求低,不用求概率密度函数而且计算简便.通过对工程实例的计算,其结果表明所提出的方法是一种简便而实用的分析方法.     

Mission reliability evaluation based on operational quality data for multistate manufacturing systems

Modern and intelligent manufacturing systems have a prominent multistate feature. However, previous studies of reliability analysis of multistate manufacturing systems mostly focused on the basic reliability of manufacturing systems but disregarded their operating characteristics, which has hindered the development of Prognostics and Health Management technique for intelligent manufacturing systems. Therefore, an evaluation approach of mission reliability for multistate manufacturing systems based on operational quality data is proposed in this paper. First, from the systematic viewpoint of the composition and operational principle of the manufacturing system, the relationship among production task execution state, production equipment degradation state, and produced product quality state is expounded, and the connotation of the mission reliability of multistate manufacturing systems is defined. Second, an extended state task network (ESTN) is presented to organise operational quality data by considering the quality state of work in process (WIP). Third, a fusion model of operational quality data for manufacturing systems is established with the aid of the ESTN, and an operational quality data-oriented evaluation method of mission reliability is been put forward. Finally, a case study of a manufacturing system for a cylinder head is conducted to verify the proposed approach.     

基于Kriging模型的充液管道共振非概率可靠性分析

为解决传统概率可靠性在解决流固耦合问题方面的不足,研究了结构不确定参量用超椭球凸集模型和区间变量共同描述下的非概率共振可靠性问题。针对隐式极限状态函数难以求解的问题,引入Kriging模型和超立方抽样技术应用于非概率可靠性分析。该方法用Kriging模型作为近似模型描述原结构,并在计算过程中不断更新近似模型。考虑管道与液体之间的耦合作用,利用有限元软件对所建立的简单管道系统进行模态计算并且结合防共振理论进行充液管路系统的流固耦合振动非概率可靠性分析,用优化的方法计算可靠性指标。工程算例分析表明该方法的合理性,能完善流固耦合管道系统的防共振可靠性分析方法与理论。     

三维结构可靠度对随机变量的敏感性研究

本文基于三维随机有限元提出了结构点可靠度、失效模式的可靠度及整个结构体系的可靠度分别对随机变量的＂分布参数＂和＂极限状态方程参数＂的敏感性计算方法，并以一典型重力坝为例进行了计算，得出了若干有益的结论。     

Structural reliability assessment by salp swarm algorithm–based FORM

The first-order reliability method (FORM) is well recognized as an efficient approach for reliability analysis. Rooted in considering the reliability problem as a constrained optimization of a function, the traditional FORM makes use of gradient-based optimization techniques to solve it. However, the gradient-based optimization techniques may result in local convergence or even divergence for the highly nonlinear or high-dimensional performance function. In this paper, a hybrid method combining the Salp Swarm Algorithm (SSA) and FORM is presented. In the proposed method, a Lagrangian objective function is constructed by the exterior penalty function method to facilitate meta-heuristic optimization strategies. Then, SSA with strong global optimization ability for highly nonlinear and high-dimensional problems is utilized to solve the Lagrangian objective function. In this regard, the proposed SSA-FORM is able to overcome the limitations of FORM including local convergence and divergence. Finally, the accuracy and efficiency of the proposed SSA-FORM are compared with two gradient-based FORMs and several heuristic-based FORMs through eight numerical examples. The results show that the proposed SSA-FORM can be generally applied for reliability analysis involving low-dimensional, high-dimensional, and implicit performance functions.     

A single-loop optimization method for reliability analysis with second order uncertainty

Reliability analysis may involve random variables and interval variables. In addition, some of the random variables may have interval distribution parameters owing to limited information. This kind of uncertainty is called second order uncertainty. This article develops an efficient reliability method for problems involving the three aforementioned types of uncertain input variables. The analysis produces the maximum and minimum reliability and is computationally demanding because two loops are needed: a reliability analysis loop with respect to random variables and an interval analysis loop for extreme responses with respect to interval variables. The first order reliability method and nonlinear optimization are used for the two loops, respectively. For computational efficiency, the two loops are combined into a single loop by treating the Karush–Kuhn–Tucker (KKT) optimal conditions of the interval analysis as constraints. Three examples are presented to demonstrate the proposed method.     

基于随机过程跨越理论的钢轨动力可靠性分析与比较

采用模态分析方法建立车辆-轨道垂向耦合动力计算模型,使用Wilson-θ数值积分方法,得到钢轨在列车荷载作用下的随机振动响应。基于随机过程跨越理论,得到在不同的跨越假设以及极值分布条件下钢轨的动力响应可靠度,并与数值模拟法计算的结果进行比较。结果表明：对于低跨越界限,极值I型分布方法的计算结果与精确值最为接近;而对于高界限,高斯分布法效果最好。     

Reliability based design optimization using response surfaces in application to multidisciplinary systems

Traditionally, reliability based design optimization (RBDO) is formulated as a nested optimization problem. For these problems the objective is to minimize a cost function while satisfying the reliability constraints. The reliability constraints are usually formulated as constraints on the probability of failure corresponding to each of the failure modes or a single constraint on the system probability of failure. The probability of failure is usually estimated by performing a reliability analysis. The difficulty in evaluating reliability constraints comes from the fact that modern reliability analysis methods are themselves formulated as an optimization problem. Solving such nested optimization problems is extremely expensive for large scale multidisciplinary systems which are likewise computationally intensive. In this research, a framework for performing reliability based multidisciplinary design optimization using approximations is developed. Response surface approximations (RSA) of the limit state functions are used to estimate the probability of failure. An outer loop is incorporated to ensure that the approximate RBDO converges to the actual most probable point of failure. The framework is compared with the exact RBDO procedure. In the proposed methodology, RSAs are employed to significantly reduce the computational expense associated with traditional RBDO. The proposed approach is implemented in application to multidisciplinary test problems, and the computational savings and benefits are discussed.