关于可靠性指标的几个问题

描述舰载雷达等电子产品的系统可靠性参数是很多的,但是MTBF和MTTR是常用的两项可靠性参数,其中MTBF预计值又是产品设计和质量管理中的基本可靠性指标。本文就我所的几个产品的可靠性指标具体地提出了一些看法,如可靠性设计指标和试验假设值的确定、合同中可靠性指标的确定以及对含义不清的指标如何正确处理等。     

浅谈LED显示和应用产品的可靠性

本文简要讨论LED显示产品的可靠性的含义,提出应以显示屏系统的MTBF和LED光衰两个特征量来描述LED显示和应用产品的可靠性和寿命。厂家应提供各种规格的箱体的MTBF．这是计算系统MTBF的基础。     

《可靠性设计》思考题

一、试简述可靠性设计的现实意义。二、进行可靠性设计,为什么必须首先制订好总体设计方案?制订总体设计方案应有哪些具体要求和准则? 三、可靠性指标有哪些不同的表示形式?当寿命服从指数分布时,不同形式指标之间有怎样的关系? 四、试述 A=MTBF/(MTBF+MTTR)和A_0=MTBF/(MTBF+MTTR+Md)的涵义。五、简述固有可靠性、使用可靠性、验证可靠性和设计可靠性的含义。六、确定一个新产品的可靠性指标时,应遵循哪几方面准则? 七、什么叫可靠性预计?有哪些常用的预计方法?它们的优缺点和适用场合是什么? 八、应力分析法可靠性预计的一般程序是什么?     

平板电视可靠性MTBF的管控论述

越来越多平板电视厂商意识到要通过提高产品的可靠性来提高品牌美誉度和降低售后三包成本.因此,该文论述了可靠性的衡量指标MTBF和统计方法,并且研究如何在开发阶段进行MTBF鉴定,以及到量产阶段仍然进行有效监控.可以直观地指导厂商进行平板电视可靠性管控.     

定时截尾试验中故障数为零的设备MTBF评估

介绍了定时截尾可靠性试验中可能遇到的故障数栅情况下的MTBF评估问题。给出了两种MTBF量值算法,并通过对某电子设备可靠性试验数据的描述,对装备可靠性做出一个较为客观、准确的评估,具有较强的操作性。     

如何建设可靠性99．99％的FTTx／H有线电视网

要为用户提供好的业务质量．FTTx／H必须达到电信级的双向业务可靠性要求（可用性99．99％，年平均中断时间不超过53分钟）的运营水平。可靠性分析中两个关键的基本数据为MTBF（或AFR）和MTTR。     

不间断电源(UPS)可靠性指标论证与分析

本文对如何确定UPS的可靠性指标（ MTBF和MTTR）进行了论证和分析,介绍了UPS在逆变器模式下和逆变器加旁路模式下MTBF的计算方法,说明了在计算UPS时应考虑的问题。     

基于Bellcore标准的电子产品可靠性预计方法及案例研究

介绍了Bellcore标准进行可靠性预计的理论基础,包括元器件失效率与单元失效率模型等。利用Bellcore现行的TelcordiaSR-332标准手册,对某用于商用环境中的单板计算机进行了可靠性预计。给出了该单板计算机MTBF预计的过程和方法,以及失效率和MTBF的预计结果,并与军用标准的预计结果进行了对比,说明了Bellcore标准目前存在的一些问题。     

石英谐振称重传感器的可靠性增长

对已批量生产的某种石英谐振称重传感器进行了可靠性增长的尝试。首先对这种传感器实施了环境试验与寿命试验，并用经典法、信赖法和贝叶斯法估计了环境可靠度及MTBF的单侧置信下限。进而对其进行失效分析，并将系统性B类失效加以改进，采用一般性的可靠性增长方式，经可靠性验证试验对增长后的MTBF做出评价，当置信水平为0．9时，其MTBF的单侧置信下限达到了299 158次；满足了MTBFL10万次的要求。并用AMSAA—BISE模型进行了增长趋势检验和拟合优度检验。     

电源模块冗余热备份对可靠性的影响

温度是影响电子设备可靠性的重要因素。介绍了高频开关电源可靠性指标MTBF的计算方法,并分析了电源模块不同热备份数量对可靠性的影响。     

Approximated reliability of r-out-of-n(F) system with common cause failure and maintenance

In modern industries very high reliability system are needed. To improve the reliability of system, the component redundancy and maintenance of component or system play an impotant role and must be studied. This paper presents a reliability model of a r-out-of-n(F) redundant system with maintenance and Common Cause Failure. Failed component repair times are arbitrarily distributed. The system is in a failed state when r units failed because of the combination of single element failure or CCF(Common Cause Failure). Laplace transformation of reliability is derived by using analysis of Markov state transition graph. By using the analyzed MTBF, we compute MTBF of r-out-of-n(F) system. The MTBF with CCF is saturable even if repair rate is large.Approximated reliability of the r-out-of-n(F) system with maintenance and Common Cause Failure O.SummaryThe paper presents a reliability model of a r-out-of-n(F) redundant system with maintenance and Common Cause Failure. Failed component repair times are arbitrarily distributed. The system is in a failed state when r units failed because of the combination of single element failure or Common Cause Failure. Laplace transformation of reliability is derived by using analysis of Markov state transition graph. By analyzing this mean visiting time equations, we compute MTBF and shows computational example. The MTBF with CCF is saturable even if repair rate is large. In general the maintenance overcomes MTBF bounds, But the repair method not overcome the MTBF saturation when the system has Common Cause Failure.     

Survey of reliability and availability evaluation of complex networks using Monte Carlo techniques

Generally there are four main difficulties in evaluating complex large-scale system reliability, availability and MTBF: the system structure may be very complex; subsystems may follow various failure distributions; subsystems may conform to arbitrary failure and repair distributions for maintained systems; the failure data of subsystems are sometimes not sufficient, reliability test sample sizes tend to be small. It is difficult and often impossible to obtain s-confidence limits of them by classical statistics. Monte Carlo technique combined with Bayes method is a powerful tool to solve this kind of problems. In this survey, the typical existing Monte Carlo reliability, availability and MTBF simulation procedures, variance reduction methods, and random variate generation algorithms are analyzed and summarized. The advantages, drawbacks, accuracy and computer time of Monte Carlo simulation in evaluating reliability, availability and MTBF of a complex network are discussed. Finally, some conclusions are drawn and a general Monte Carlo reliability and MTTF assessment procedure is recommended.     

Starting & Limiting Values for Reliability Growth

Modifications of the Duane model for reliability growth which permit formulating test plans prior to test-data availability are presented herein. The modified model yields finite and nonzero MTBFs at the start and end of development testing. The unmodified Duane model is inadequate for formulating the Development Test plan for a Reliability Program because the MTBF is zero at the start of testing and is unbounded for long tests. The parameters of the modified model; limiting MTBF, initial MTBF, and Duane shape parameter (logarithmic growth rate) are estimatable from handbooks and previous experience prior to the start of development tests. An implicit expression for the Duane-model scale-parameter as a function of the limiting MTBF, initial MTBF, and shape parameter is given. The time required and/or the reliability improvement potential of development tests are obtained from the model to plan the reliability program. When the development tests are underway interval estimates for the modified Duane model parameters, needed to monitor the progress of the reliability program, can be computed.     

软件第三方定型测评与质量保证

软件第三方定型测评是装备配套软件研发过程中的重要环节,对软件质量保证至关重要。加强对软件第三方测评的质量监控,能够提高软件可靠性,从而大大提高装备效能。文中介绍了软件第三方测评的相关知识、软件质量保证的方法以及二者之间的关系,并以典型电子信息系统软件的定型测评为例进行了验证。验证结果表明,软件第三方定型测评可以使该系统软件质量得到保证和提高。     

无线终端指纹仪可靠性试验探讨

可靠性试验是一种验证试验。验证试验就其方法而言是一种抽样检验程序,与其他抽样验收的区别在于,它考虑的是与时间有关的产品质量特性,如平均故障间隔时间(MTBF)。因此,产品可靠性指标的验证工作原理是建立在一定寿命分布假设的基础上。在实际工作中为了验证无线终端指纹仪的可靠性是否满足标准要求,制订了相应的检测大纲,对其可靠性试验进行了探讨。     

基于物联网典型应用的智能家居MTBF自动化测试

根据对物联网典型应用的研究分析,提出了把智能家居不同种类应用抽象为"类黑盒"的研究方法。同时,为了让被测产品的可靠性可以进行量化评估,引入了MTBF评估指标以及自动化测试方法。在上述研究的基础上,构建了智能家居测试系统,该系统把真实的设备抽象为不同应用接口服务,通过测试脚本进行控制,实现了透明仿真测试,使得产品测试及指标标准化,能够有效地验证产品的功能和可靠性,从而提高了测试效率和准确性。     

基于商用手机的全员测试分析系统的研究

通过对移动网络测试方法便捷、高效、低成本、真实性的研究,提出了一种基于Android操作系统普通商务手机的信号电平检测系统方案,开发出可以运行在任意一款Android终端上的客户端软件,能够捕获手机信号电平、位置等数据进行移动通信网络覆盖、质量、速率的分析和优化。并创造性设计木马测试版本,通过后台服务器端发送命令启动客户端进行测试,无需客户端开启软件,实现了后台控制前台功能。     

Relcomp: A Computer Program for Calculating System Reliability and MTBF

A conversational time-sharing computer program called Relcomp can be used for rapid and economical calculation of the reliability and mean time between failures (MTBF) of systems consisting of serial and redundant units. Relcomp is simple to use and does not require any special knowledge of programming. A copy of the complete Relcomp program listing is provided in Tymshare Super Basic language. Use of the program to calculate the reliability and MTBF of a system, its subsystems, and blocks is illustrated by examples.     

Reliability analysis and comparison of several structures

In this study, we consider the redundant structure with the function of swithover processing which is assumed to cause the increase of the failure rate of the system. A single component system and a simple redundant system are compared in terms of the four reliability measures such as the reliability function, the MTBF, the failure rate and the mean residual life (MRL). We find the relations of the MTBF, the failure rate, and the MRL between two systems. We also consider a quad configuration system and a parallel string configuration system and evaluate the four reliability measures for two systems. As a numerical example, the total system down of an ATM switching system is considered.