Acceleration Factor Constant Principle and the Application under ADT

2016 ◽  
Vol 32 (7) ◽  
pp. 2591-2600 ◽  
Author(s):  
Hao-Wei Wang ◽  
Wen-Jun Xi
Keyword(s):  
Acceleration Factor ◽  
Factor Constant

Design of an Optimal Plan of Accelerated Degradation Test via Acceleration Factor Constant Principle

2018 ◽  
Vol 25 (05) ◽  
pp. 1850021 ◽  
Author(s):  
Fei Teng ◽  
Hao-Wei Wang ◽  
Yuan Zhou
Keyword(s):  
Optimal Design ◽  
Design Method ◽  
Asymptotic Variance ◽  
Acceleration Factor ◽  
Degradation Model ◽  
Accelerated Degradation ◽  
Optimal Design Method ◽  
Degradation Test ◽  
Accelerated Degradation Test ◽  
Factor Constant

Accelerated degradation test (ADT) has been extensively applied to reliability assessment. To improve the efficiency–cost ratio of ADT, the optimal design method of ADT has become a research hot topic. An optimal design method based on acceleration factor, in which a Wiener degradation model and a step-stress ADT were considered, was proposed in the paper. In order to establish an accurate accelerated degradation model, acceleration factor constant principle was applied to derive the changing rules of Wiener process parameters with accelerated stress. Besides, the exact expression of acceleration factor was determined for a Wiener degradation model. The asymptotic variance of acceleration factor, which was considered as a measure of the consistency of failure mechanisms, was selected to be the objective function of optimal problem so as to ensure that the failure mechanism of products under accelerated stresses is probably consistent with that under the normal use stresses. A numerical example of designing an optimal ADT plan for a certain type electrical connector was studied, in which the effectiveness and feasibility of the proposed method were validated.

scholarly journals Nonlinear Doubly Wiener Constant-Stress Accelerated Degradation Model Based on Uncertainties and Acceleration Factor Constant Principle

2021 ◽  
Vol 11 (19) ◽  
pp. 8968
Author(s):  
Xiaoning Wang ◽  
Xiaobao Su ◽  
Jinjing Wang
Keyword(s):  
Applied Stress ◽  
Measurement Errors ◽  
Constant Stress ◽  
Acceleration Factor ◽  
Process Models ◽  
Unknown Parameters ◽  
Degradation Model ◽  
Practical Applications ◽  
Accelerated Degradation ◽  
Factor Constant

Although Wiener process models with the consideration of uncertainties, which are nonlinearity, random effects, and measurement errors, have been developed for lifetime prediction in the accelerated degradation test (ADT), they fail to describe the real degradation process because these models assume that the drift parameter correlates with the applied stress, while the diffusion parameter is constant. This paper put forward a nonlinear doubly Wiener constant-stress accelerated degradation model, where both diffusion and drift parameters were compatible with the applied stress according to the acceleration factor constant principle. When degradation data were available, we obtained the unknown parameters by applying a maximum likelihood estimation (MLE) algorithm in the constant-stress ADT (CSADT) model taking uncertainties into account. In addition, the proposed model’s effectiveness was validated through an illustrative example, and an application to the traveling wave tube (TWT) was carried out to demonstrate the superiority of our model in practical applications.

PLANNING FOR ACCELERATED LIFE TESTS

1999 ◽  
Vol 06 (03) ◽  
pp. 265-275 ◽  
Author(s):  
LOON-CHING TANG
Keyword(s):  
Acceleration Factor ◽  
Test Time ◽  
Initial Sample ◽  
Lower Stress ◽  
Nonlinear Programs ◽  
Accelerated Life Tests ◽  
Accelerated Life ◽  
Stress Levels ◽  
Life Tests ◽  
Sample Allocation

We present two alternative perspectives to the current way of planning for constant-stress accelerated life tests (CSALTs) and step-stress ALT (SSALT). In 3-stress CSALT, we consider test plans that not only optimize the stress levels but also optimize the sample allocation. The resulting allocations also limit the chances of inconsistency when data are plotted on a probability plot. For SSALT, we consider test plans that not only optimize both stress levels and holding times, but also achieve a target acceleration factor that meets the test time constraint with the desirable fraction of failure. The results for both problems suggest that the statistically optimal way to increase acceleration factor in an ALT is to increase lower stress levels and; in the case of CSALT, to decrease their initial sample allocations; in the case of SSALT, to reduce their initial hold times. Both problems are formulated as constrained nonlinear programs.

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