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。     

考虑测试影响的武器装备贮存寿命预测

为确保武器装备的可靠性,需定期或不定期地对其性能进行监测,且每次监测需要多次测试。针对武器装备贮存寿命预测中未考虑测试影响,由此造成直接使用监测的性能退化数据进行贮存寿命预测时预测结果不准确的问题,提出一种考虑测试影响的武器装备贮存寿命预测方法。该方法根据武器装备在贮存期间是否监测将其退化过程分为贮存状态和工作状态,据此建立了一种新的退化模型,通过贝叶斯理论和EM算法将反映贮存状态和工作状态的退化模型参数进行分离,得到了贮存寿命的预测结果。最后,通过装备性能监测数据对其在贮存期间的退化轨迹进行了预测,且与传统贮存寿命预测方法进行了比较,验证了所提方法的实用性和有效性。     

深度黑盒型设备贮存寿命评估方法研究

本文提出一种基于深度黑盒型设备内部典型元器件的寿命特征和性能退化规律,评估其贮存寿命的方法.即将黑盒型设备分解成元器件,通过对随设备长期贮存的典型元器件进行寿命特征诊断,针对寿命特征良好的元器件再开展加速退化试验,掌握其关键性能参数的退化规律,评估深度黑盒型设备的贮存寿命.     

融合非线性加速退化模型与失效率模型的产品寿命预测方法

针对高可靠性产品寿命数据少、获取成本高的问题,基于充分利用产品在研制、加速试验等不同环境下的退化数据、失效数据等可靠性数据的思想,提出了一种融合非线性加速退化模型和失效率模型的产品寿命预测方法.首先,根据退化数据对非线性退化过程进行分析,估计退化过程的参数;然后,根据加速退化数据及相应的加速退化模型估计加速退化模型的参数,从而得到退化参数与应力之间的关系.进一步,利用比例风险模型融合产品的寿命数据和未失效截尾数据,并基于此计算产品的可靠度函数、预测产品的寿命.实例应用验证了所提方法的有效性,同时说明了所提方法的应用价值.     

电子倍增器的加速试验方法及其寿命预测研究

对电子倍增器的加速试验方法及其寿命预测理论进行了研究.首先,建立了电子倍增器加速退化试验系统,设计了加速退化试验方案;然后,对电子倍增器进行了加速退化试验;最后,提出了电子倍增器的双恒定应力加速退化试验数据的分析方法,并对分析结果进行了模型检验分析,验证了该方法的有效性.     

IC长贮存寿命评价方法

高可靠长寿命产品在军事、航空航天、电子工业、通信等领域应用越来越广泛,如何保障其可靠性与预测其寿命是值得深入研究的重要问题。越来越多的单位,特别是航空航天系统的单位,对其选用的产品提出了具有32年贮存寿命要求的高可靠性指标。长寿命及超长寿命的电子元器件的贮存寿命评价是以加速试验为评价方法的。建立准确的失效机理及模型是评价正确与否的关键。文章通过收集大量高温贮存及常温贮存的实测数据,建立失效模型,推算出应力条件及相应的加速因子。文中实践证明,通过模型仿真出的贮存寿命具有高的可信度。     

基于加速退化模型的加速度开关贮存寿命评估

贮存寿命是长使用周期、高可靠性产品的重要考核指标之一。为评估某型加速度开关的贮存寿命,该文采用温度应力四量级水平恒定应力加速试验方法研究了加速度开关的退化过程,并将阿伦尼斯加速模型与漂移布朗运动相结合,建立了产品的可靠性模型。最后采用极大似然和最小二乘法对试验数据进行了拟合分析。结果表明,某型加速度开关在100℃的加速量级下,其等效贮存年限可达33年,满足产品有效贮存期的要求。     

引进产品贮存可靠性试验评价方法探讨

提出了一种基于性能退化的贮存加速试验和元器件贮存寿命特征检测分析相结合的方法来进行引进产品电子部件贮存可靠性试验评价研究,并介绍了贮存加速退化试验和寿命特征检测的有关方法。     

基于LSSVM的小子样元器件寿命预测

现代高可靠元器件在寿命试验时会出现失效数据很少的小子样情形,而传统的可靠性评估方法需要大量的失效数据,针对此情况,从工程实践的实际需求出发,提出了基于最小二乘支持向量机的小子样元器件寿命预测方法。该方法通过建立最小二乘支持向量机模型,从而可根据已知元器件的失效时间去直接预测同一批未失效元器件的失效时间。将该方法应用于热载流子效应引起MOS管退化失效的加速寿命试验中进行MOS管失效时间的预测,结果表明基于最小二乘支持向量机的寿命预测方法在进行小子样元器件的寿命预测时具有很高的精确度。     

高温贮存寿命评估试验

元器件分别进行常温储存试验和高温贮存试验,通过常温储存试验累积试验数据并以此研究总结元器件长期储存性能参数变化规律和失效模式。通过高温贮存试验加速元器件常温储存过程累积试验数据,根据关键参数随加速试验的变化情况,得到高温贮存条件相对常温储存条件的加速因子,根据加速因子得到加速贮存试验的时间,在该高温点下进行相应时间的加速贮存试验。试验结果即为常温特定年限储存寿命的预计结果,从而在较短的时间内对元器件长期储存寿命做出评定。     

宇航用光纤陀螺双应力步进加速退化技术

光纤陀螺在宇航环境中会承受多种环境应力的作用,针对光纤陀螺在单一加速应力作用下的极限问题,提出双应力交叉步进加速退化试验方法,实现了寿命和可靠性评估。通过建立包含剩余标准化系数的退化轨迹模型,描述了光纤陀螺退化量与应力水平的关系。基于累积损伤模型及时间折算的模型参数估计方法进行加速退化数据的统计分析,得到光纤陀螺在使用应力水平下的寿命及可靠性信息。以光纤陀螺为对象,验证了此方法的有效性。     

斯特林制冷机污染退化的加速寿命模型

基于制冷机的污染失效机理、材料出气特性,探索性地提出制冷机污染退化的加速寿命模型,阐述了各模型参数的物理意义,并利用4300h的加速试验数据建模拟合,发现与加速寿命模型有较好的符合关系,最后提出外推到常规条件寿命的加速系数的计算方法.由于试验数量少,所得模型尚不成熟,需要更多的后续试验来验证,但该寿命模型的提出,对于实现快速寿命评价和考核具有参考价值.     

Development of a lifetime prediction model for lithium thionyl chloride batteries based on an accelerated degradation test

Battery life prediction is critical for lithium/thionyl chloride cells with a long storage life. The objective of this study was to develop models for rapidly estimating the storage life of Li/SOCl₂ cells using the semiempirical approach. An accelerated degradation test involving numerous cells stored at various temperatures (room temperature or RT, 40, 50, 60, and 70 °C) was conducted to investigate the effect of the storage time and temperature on capacity degradation. The degradation law can be summarized on the basis of the test data for constructing the semiempirical equation; this law demonstrates that the residual capacity of aging cells exponentially changes with the storage time and temperature. The degradation data are also used for parameterization with the multiple nonlinear curve fitting method based on the universal global optimization algorithm. According to the simulation and comparison between the experimental data and prediction curve, the fitting prediction curve accurately fits the experimental data. This finding indicates that the semiempirical model is useful because of its satisfactory ability to approximate the measured data. In addition, characteristic values of the battery, including the storage life under various storage conditions, average self-discharge rate, and acceleration factor, can be calculated on the basis of the mathematical model.     

基于加速退化的电子设备可靠性分析

提出了电子设备在退化状态下的可靠性分析问题,通过建立电子设备退化失效模型与失效阈值,解决了有正常退化数据的电子设备可靠性问题。在此基础上,研究了加速退化时的电子设备退化问题,利用加速试验来分析电子设备在非加速状态下的退化失效,从而解决了非加速状态时退化数据不足以进行可靠性分析的问题。最后,给出了计算实例。     

Optimal Step-Stress Accelerated Degradation Test Plan for Gamma Degradation Processes

Step-stress accelerated degradation testing (SSADT) is a useful tool for assessing the lifetime distribution of highly reliable products (under a typical-use condition) when the available test items are very few. Recently, an optimal SSADT plan was proposed based on the assumption that the underlying degradation path follows a Wiener process. However, the degradation model of many materials (especially in the case of fatigue data) may be more appropriately modeled by a gamma process which exhibits a monotone increasing pattern. Hence, in practice, designing an efficient SSADT plan for a gamma degradation process is of great interest. In this paper, we first introduce the SSADT model when the degradation path follows a gamma process. Next, under the constraint that the total experimental cost does not exceed a pre-specified budget, the optimal settings such as sample size, measurement frequency, and termination time are obtained by minimizing the approximate variance of the estimated MTTF of the lifetime distribution of the product. Finally, an example is presented to illustrate the proposed method.      

用高低温循环加速试验评估光源模块长期贮存寿命的研究

Light source modules are the most crucial and fragile devices that affect the life and reliability of the interferometric fiber optic gyroscope （IFOG）. While the light emitting chips were stable in most cases, the module packaging proved to be less satisfactory. In long-term storage or the working environment, the ambient temperature changes constantly and thus the packaging and coupling performance of light source modules are more likely to degrade slowly due to different materials with different coefficients of thermal expansion in the bonding interface. A constant temperature accelerated life test cannot evaluate the impact of temperature variation on the performance of a module package, so the temperature cycling accelerated life test was studied. The main failure mechanism affecting light source modules is package failure due to solder fatigue failure including a fiber coupling shift, loss of cooling efficiency and thermal resistor degradation, so the Norris-Landzberg model was used to model solder fatigue life and determine the activation energy related to solder fatigue failure mechanism. By analyzing the test data, activation energy was determined and then the mean life of light source modules in different storage environments with a continuously changing temperature was simulated, which has provided direct reference data for the storage life prediction of IFOG.     

Empirical prediction model for Li/SOCl2 cells based on the accelerated degradation test

The empirical prediction model of residual capacity (Cap) for D-size Li/SOCl₂ cells has been developed and validated based on the accelerated degradation test (ADT) data. In this experiment, a series of constant storage temperatures (25 °C, 55 °C, 70 °C, and 85 °C) was selected and the residual capacity of each cell was monitored continuously during the aging test. The model was established by fitting twice. Firstly, time dependence of Cap (t, T) was investigated. Secondly, the generalized model of residual capacity was built. The prediction model, as a function of storage time and temperature, can precisely predict the value of residual capacity. The generalized empirical model of Cap, involving two aging processes, is valid for the degradation condition of temperatures from 25 °C to 70 °C. The first aging process completed rapidly within 7 days. The second aging process was accelerated by temperature with time^1/2 kinetics. For the cells stored at 85 °C, another failure mechanism may exist based on the departure of linear fitting coefficients.     

恒加试验下LED照明灯的三参数Weibull分布的参数估计

三参数Weibull分布拟合LED照明灯寿命的优势较为明显,但要得到三参数Weibull分布参数较为精确的点估计较为困难。目前常用的参数估计方法有极大似然法、矩估计法、Bayes估计法等,由于其计算的方程复杂,导致软件编程繁琐,不易掌握,而且也不一定能得到参数估计。鉴于此,文章针对恒加试验提出一种简便地求解三参数Weibull分布参数估计的方法,该方法不涉及超越方程的求解问题,软件编程相当简单,且统计思想清晰。通过LED照明灯恒加试验下的几个案例数据说明方法的应用,并与已有的方法做了对比分析。     

Analyzing accelerated degradation data by nonparametric regression

This paper presents a nonparametric regression accelerated life-stress (NPRALS) model for accelerated degradation data wherein the data consist of groups of degrading curve data. In contrast to the usual parametric modeling, a nonparametric regression model relaxes assumptions on the form of the regression functions and lets data speak for themselves in searching for a suitable model for data. NPRALS assumes that various stress levels affect only the degradation rate, but not the shape of the degradation curve. An algorithm is presented for estimating the components of NPRALS. By investigating the relationship between the acceleration factors and the stress levels, the mean time to failure estimate of the product under the usual use condition is obtained. The procedure is applied to a set of data obtained from an accelerated degradation test for a light emitting diode product. The results look very promising. The performance of NPRALS is further checked by a simulated example and found satisfactory. We anticipate that NPRALS can be applied to other applications as well