Step-stress accelerated testing of high-power LED lamps based on subsystem isolation method

Cai, Miao; Yang, Daoguo; Tian, Kunmiao; Zhang, Ping; Chen, Xianping; Liu, Lilin; Zhang, Guoqi

doi:10.1016/j.microrel.2015.06.147

Cited by 36 publications

(19 citation statements)

References 10 publications

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“…where 0 denotes the normal working stress, is the maximum accelerated stress, 0 = 0 < 1 < ⋅ ⋅ ⋅ < = 1. The CSADT and the SSADT have been widely used in all kinds of product tests, such as LED [18], electrical connector [17], and SLD [19]. We suppose that there are units participating in ADT from the beginning of the experiment 0 = 0 to cut-off time .…”

Section: Modeling Of Accelerated Degradationmentioning

confidence: 99%

A Modeling Method of Stochastic Parameters’ Inverse Gauss Process Considering Measurement Error under Accelerated Degradation Test

Cui

et al. 2019

Mathematical Problems in Engineering

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To solve the problem that the individual differences and the measurement errors affect the accuracy of life estimation in accelerated degradation test, the inverse Gauss process with stochastic parameters is applied in the accelerated degradation test with the consideration of the influence of individual differences, and the analysis of measurement uncertainty is carried out. An inverse Gauss accelerated degradation model considering both individual differences and measurement errors is established. In the maximum likelihood estimation of parameters, Genetic Algorithm and Monte Carlo integral are used to solve the problems caused by complex integral and the unobservable measurement errors in the calculation process. Finally, the proposed method is verified by the Monte Carlo simulation under the constant accelerated stress and step accelerated stress and the illustrative example of electrical connectors under the constant acceleration stress, respectively. The results show that the modeling tool is useful for improving the accuracy of the life prediction and the reliability evaluation.

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Section: Modeling Of Accelerated Degradationmentioning

confidence: 99%

A Modeling Method of Stochastic Parameters’ Inverse Gauss Process Considering Measurement Error under Accelerated Degradation Test

Cui

et al. 2019

Mathematical Problems in Engineering

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“…On the other hand, a few techniques were also proposed for the judgment of mechanism consistency in accelerated tests. They are -statistic distribution analysis [44], activation energy calculation [45,46], and independent parameters in degradation models [18,19]. Step stress pattern with different stress factors…”

Section: B Ssadt Modeling By Using Brownian Motion Processmentioning

confidence: 99%

“…In general, constant stress accelerated degradation test (CSADT) and step stress accelerated degradation test (SSADT) are two of the most popular ADTs in industry applications. Compared to CSADT, SSADT enables comparable lifetime prediction accuracy while using smaller sample size and less test resources [18][19][20]. Therefore, the SSADT has been widely applied in reliability tests for LEDs [21,22], transistors [23], and missile tanks [24].…”

mentioning

confidence: 99%

Lumen degradation modeling of white-light LEDs in step stress accelerated degradation test

Huang

Golubović²,

Koh

et al. 2016

Reliability Engineering & System Safety

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In this paper, lumen degradation is described by using a modified Brownian motion process for mid-power white-light LED packages, which were aged under step stress accelerated degradation test (SSADT). First, a SSADT model has been established based on the theory of equivalent accumulative damage. Then, a method was proposed to improve the accuracy of the parameter estimation by carefully modifying the estimator, which was proposed in the previous research. Experimental data show that parameters estimated by using SSADT model are very close to those estimated by using constant stress accelerated degradation test (CSADT) model, indicating the feasibility of the SSADT model. The experiment also indicates that SSADT can be used as an alternative to CSADT, as it enables comparable estimation accuracy, while using less testing time, a smaller sample size and less test capacity. Index Terms-accelerated test; Brownian motion; degradation test; light-emitting diodes; step stress; Wiener process I. INTRODUCTION ID-POWER white-light LEDs (MP-LEDs) have been widely considered as the new generation of luminaires due to their advantages of higher efficiency, longer lifetime, and more environment protections as compared to currently widely used lighting solutions (incandescence, fluorescence). Recently, due to fast evolution of the technologies, the lifetime of LED packages has been claimed to be as high as 50,000 hours. For such kind of products, failed units would be seldom observed during life tests, even though they are subjected to accelerated conditions. Therefore, it is unreasonable to collect Manuscript received

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“…SSADT has an advantage over CSADT since it allows a comparable assessment accuracy with a lower sample size [4]. Therefore, the last few decades have witnessed wide application of SSADT in reliability tests for LEDs [5], electrical connectors [6], missile tanks [7] and transistors [8]. The purpose of this study is to model the SSADT process in a more practical way, and the emphasis is to handle with various sources of variability simultaneously.…”

Section: Introductionmentioning

confidence: 99%

Nonlinear step-stress accelerated degradation modelling considering three sources of variability

Hao

Yang

Bérenguer

2018

Reliability Engineering & System Safety

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In the absence of enough run-to-failure data, step-stress accelerated degradation testing (SSADT) is often an attractive alternative way to evaluate the reliability of a product, with the advantage of requiring small sample size and short test time. However, the development of a statistical SSADT model for reliability assessment should take into account different sources of variability in the degradation process that generate uncertainty: 1) temporal variability determining the inherent variability of degradation process over time; 2) unit-to-unit variability in three aspects: degradation rates, initial degradation values, time-points of elevating stress levels; and 3) measurement errors in both covariates and degradation performance. As a contribution towards this aim, a new nonlinear Wiener-process-based SSADT model considering simultaneously nonlinearity and three sources of variability is proposed. Using the proposed SSADT model, the lifetime law of the tested product under normal conditions is derived based on the concept of first hitting time (FHT) of a predetermined failure threshold. Following an approach based on genetic algorithms (GA), a modified simulation and extrapolation method, called GA-SIMEX, is also developed for the model parameter estimation. Finally, a simulation study of fatigue crack length growth is presented to illustrate the implementation of the proposed SSADT model.

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Step-stress accelerated testing of high-power LED lamps based on subsystem isolation method

Cited by 36 publications

References 10 publications

A Modeling Method of Stochastic Parameters’ Inverse Gauss Process Considering Measurement Error under Accelerated Degradation Test

A Modeling Method of Stochastic Parameters’ Inverse Gauss Process Considering Measurement Error under Accelerated Degradation Test

Lumen degradation modeling of white-light LEDs in step stress accelerated degradation test

Nonlinear step-stress accelerated degradation modelling considering three sources of variability

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