对数正态分布下基于MAM的VFD加速寿命试验研究

为了在较短时间内掌握真空荧光显示器(VFD)的寿命信息,节省寿命试验时间,通过开展两组恒定应力加速寿命试验和一组步进应力加速寿命试验,采用对数正态分布函数描述VFD的寿命分布,在图分析法(MAM)的基础上,基于MATLAB软件强大的计算和可视化绘图功能,绘制了对数正态概率双坐标纸,估计了对数均值和对数标准方差,完成了VFD恒定应力和步进应力加速寿命试验数据的统计和分析.结果表明,VFD寿命服从对数正态分布,其加速模型符合阿伦尼斯方程,基于MATLAB的图分析法来实现寿命数据处理是可行的,精确估算的加速参数使得快速预测VFD寿命成为可能.     

基于BRM的白光OLED恒定与步进应力加速寿命试验研究

为了获得白光OLED的寿命信息,通过加大电流应力开展了二组恒定和一组步进应力相组合的加速寿命试验。采用威布尔函数描述白光OLED的寿命分布,利用双线性回归法(BRM)估计出威布尔参数,确定了加速寿命方程,对白光OLED寿命是否符合威布尔分布进行了Kolmogorov-Smirnov检验,并利用自行开发的寿命预测软件计算出平均寿命和中位寿命。数值结果表明,恒定步进应力加速寿命试验方案是切实可行的,白光OLED的寿命服从威布尔分布,寿命应力关系满足线性Arrhenius方程,精确计算的加速参数可实现在短时间内OLED寿命的预测。     

简单步进加速寿命试验下指数寿命产品的BAYES统计分析

1 问题的提出与基本假定1.1 问题的提出步进应力加速寿命试验是产品进行可靠性寿命试验的常用方法,对其试验数据的统计分析,通常是要求知道产品的寿命分布的有关参数与所施加的应力之间有已知的加速寿命模型,而一切的统计分析方法均以此为依据,但在一些实际问题中,加速寿命模型并不知道。本文针对这一情况,采用Bayes分析技术,给出在步进应力加速寿命试验下产品寿命数据的统计分析方法.1.2 基本假定本文给出的统计分析方法是建立在下面几个基本假定之下的。假定1 正常应力水平的S_0,加速应力水平为S_1,S_2,满足     

电子元器件加速寿命试验方法的比较

加速寿命试验作为可靠性试验的一个组成部分,是控制、提高电子产品可靠性的常用方法.目前有三种加速寿命试验方法:恒定应力、步进应力和序进应力加速寿命试验.简要介绍了加速寿命试验的概念,举例说明这三种方法的实施方案及数据处理,从实际操作角度比较了三种方法的优、缺点,并对其应用情况做了介绍.     

GaAs红外发光二极管加速寿命试验研究

本文采用步进应力的试验方法设计了一个针对GaAs红外发光二极管的可靠性加速寿命的研究方案.这种方法主要是把步进应力和恒定应力两种方法相结合,用此来评估GaAs红外发光二极管的可靠度;然后总结除了GaAs红外发光二极管这种光电器件的寿命分布形式和失效模式.     

温度应力下基于步进加速退化试验的电子器件寿命预测

为实现高可靠性长寿命电子器件的寿命预测,根据Arrhenius模型,结合产品的线性退化轨迹模型,对于温度应力下性能退化性步进加速寿命试验,提出一种不同温度应力下时间折算方法,并且推导了它们之间的变化计算公式。在四种不同的温度下,对某型号集成运放进行步进加速试验,并利用此方法处理数据。结果表明,样品的伪寿命符合对数正态分布,其加速模型符合Arrhenius加速方程,据此可以求出样品中位寿命,实现寿命预测。     

真空荧光显示屏恒定及步进应力加速寿命试验的研究

为了解决在较短的时间内预测真空荧光显示屏（VFD）寿命的问题,降低寿命预测成本,通过加大灯丝温度进行了恒定和步进应力相组合的加速寿命试验,研究制定了其加速寿命试验的设计方案。应用威布尔分布函数描述其寿命分布,利用最小二乘法完成了试验数据的统计和分析,并开发了寿命预测软件。研究结果表明．试验设计方案是正确可行的,VFD的寿命服从威布尔分布,其加速模型符合阿伦尼斯方程,加速参数的精确计算确保以后在很短的时间内便可估算出VFD在正常应力下的寿命。     

竞争失效产品步进加速寿命试验的优化设计

对weibull分布竞争失效产品的步进加速寿命试验进行优化设计,首先选取产品正常应力下中位寿命的极大似然计估渐近方差的估计值作为优化目标函数,并对优化目标函数进行统计推断.然后利用目标函数的连续性,提出基于离散数据的函数拟合方法,将试验优化设计转化为显函数的约束极值求解问题,同时将智能优化算法应用到步进加速寿命试验的优...     

基于MAM的真空荧光显示器寿命预测

为了在短时间内得到真空荧光显示器(VFD)的寿命信息,降低寿命预测成本,通过加大阴极温度开展了恒定和步进应力加速寿命试验,建立了加速寿命试验模型,采用威布尔函数描述VFD的寿命分布,在图分析法(MAM)的基础上,基于MATLAB软件强大的计算和可视化绘图功能,绘制了威布尔概率双坐标纸,估计了加速参数,完成了VFD寿命的预测.试验数据的统计和分析结果表明,VFD在各加速应力水平下的失效机理不变,加速模型符合线性的阿伦尼斯方程,基于MATLAB的图分析法使得短时间内精确预测VFD的寿命成为可能.     

步进应力加速寿命试验数据处理方法研究

本文用ＤＢＡＳＥ语言编制了特征值时序处理程序，提出了用时序处理步进应力加速寿命试验数据的新方法。     

Analysis of grouped and censored data from step-stress life test

This paper studies statistical analysis of grouped and censored data obtained from a step-stress accelerated life test. We assume that the stress change times in the step-stress life test are fixed and the lifetimes observed are type I censored. Maximum likelihood estimates and asymptotic confidence intervals for model parameters are obtained. We provide an asymptotic statistical test for the cumulative exposure model based on the grouped and type I censored data. We also present the optimum test plan for a simple step-stress test when the lifetime under constant stress is assumed exponential. Finally we give an application of our methods by applying our analysis process to a real life data set. The proposed statistical methodology is especially useful when intermittent inspection is the only feasible way of checking the status of test units during a step-stress test.     

Step-stress life-testing with random stress-change times forexponential data

This paper studies statistical models in step-stress accelerated life-testing when the stress-change times are random. The marginal lifetime distribution of a test unit under a step-stress test plan when the stress change times are random variables is presented. Maximum likelihood estimates for model parameters based on both the marginal and conditional life distributions are considered. An optimum test plan is explored for simple step-stress test when the stress change time is an order statistic from the exponential lifetime under the low-stress level     

Accelerated Life Testing?Step-Stress Models and Data Analyses

This paper presents statistical models and methods for analyzing accelerated life-test data from step-stress tests. Maximum likelihood methods provide estimates of the parameters of such models, the life distribution under constant stress, and other information. While the methods are applied to the Weibull distribution and inverse power law, they apply to many other accelerated life test models. These methods are illustrated with step-stress data on time to breakdown of an electrical insulation.     

Si微波功率晶体管加速寿命试验夹具的设计

温度应力的加速寿命试验结果与所用夹具的耐温性及壳温的精确测量与控制直接相关。通过大量研究,发现一体式夹具在试验壳温提高到某一值时性能迅速劣化,因此设计符合高温下使用的分离式夹具是加速寿命试验顺利进行的必要条件。提供了两种加速寿命试验夹具的设计思路,并用于Si微波功率管加速寿命试验,通过步进应力试验和恒定应力试验,获取了该Si微波功率管加速寿命。分体夹具可耐受的试验温度在260℃以上,为加速寿命试验提供了温度应力的提升空间。     

Some properties of confidence bounds on reliability estimation for parts under varying stresses

Reliability estimation is usually performed on a part under a constant stress level. However, a part could experience several different stress levels, or profiled stress, during its lifetime. One such example is when the part is subject to step-stress accelerated life testing. Studying the reliability estimation & its confidence bounds for a part under varying stresses will generalize the existing estimation methods for accelerated life testing. In this paper, we derive the reliability function of a part under varying stresses based on a Weibull failure time distribution, and cumulative damage model. The reliability confidence bounds, based on a s-normal approximation, are given explicitly, and their limiting properties are discussed. A step-stress accelerated life testing example is used to illustrate these interesting properties, which provides the insights of the limitation of the current test plan, and how to design a better one.     

航天InGaAs短波红外探测器步进应力加速寿命试验研究

随着航天应用InGaAs短波红外探测器的迅速发展,其可靠性问题日益突出。选择温度为加速应力,通过步进应力加速寿命试验方法对800×2双波段集成的InGaAs焦平面探测器进行了研究,获得了InGaAs焦平面模块失效机理保持不变的最大温度应力范围和失效模式,利用温度斜坡模型计算得到了样品的失效激活能,为进一步研究该器件的可靠性问题提供了依据。     

某制导弹药电子延时器长贮退化原因探析

通过对某制导弹药电子延时器进行失效模式分析及仿真模拟,探寻可能出现的长贮失效模式与原因。以自然贮存9年的电子延时器为样本,制订了步进温度应力加速退化试验方案,开展试验并对试验结果进行分析,得出可能导致产品退化的各种原因。     

A new model for step-stress testing

The mathematical intractability of the Weibull cumulative exposure model (CE-M) has impeded the development of statistical procedures for step-stress accelerated life tests. Our new model (KH-M) is based on a time transformation of the exponential CE-M. The time-transformation enables the reliability engineer to use known results for multiple-step, multiple-stress models that have been developed for the exponential step-stress model. KH-M has a realistically appealing proportional-hazard property. It is as flexible as the Weibull CE-M for fitting data, but its mathematical form makes it easier to obtain parameter estimates and standard deviations. Maximum likelihood estimates are given for test plans with unknown shape parameter. The mathematical similarity to the constant-stress Weibull model is shown. Chi-square goodness of fit tests are performed on simulated data to compare the fit of the models     

Analysis of a simple step-stress life test with a random stress-change time

This paper studies a variation of a simple step-stress life testing in which the stress change time is random, and the test is subject to type II censoring. We assume that only two order statistics from the test are observed. The first observed order statistic is the stress change time from a low level stress to a high level stress during the testing, and the second observed order statistic is the final failure time when the test is censored. We first present the joint probability distribution of the two order statistics observed from the simple step-stress accelerated life test. Maximum likelihood estimates, and the method of moment estimates for model parameters based on the joint distribution are considered. We also present the exact confidence interval estimates for the model parameters based on various pivotal quantities, and demonstrate the estimation procedure by a simulated example.     

基于LSM的红外LED加速寿命试验数据的统计分析

利用最小二乘法(LSM)完成了红外发光二极管(LED)恒定与步进应力加速寿命试验数据的统计分析,并自行开发了可视界面和通用性强的寿命预测软件.数值结果证实了红外LED的寿命服从对数正态分布以及加速寿命方程完全符合逆幂定律,并精确地计算出预测该器件寿命所用到的关键性参数,从而使其在很短的时间(1000h)内估算寿命成为可能.