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Predicting lifetime by degradation tests: A case study of ISO 10995
Author(s) -
Fang Guanqi,
Rigdon Steven E.,
Pan Rong
Publication year - 2018
Publication title -
quality and reliability engineering international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.913
H-Index - 62
eISSN - 1099-1638
pISSN - 0748-8017
DOI - 10.1002/qre.2320
Subject(s) - failure rate , reliability (semiconductor) , accelerated life testing , reliability engineering , relative humidity , degradation (telecommunications) , stress (linguistics) , standard error , accelerated failure time model , statistics , computer science , mathematics , engineering , thermodynamics , proportional hazards model , telecommunications , power (physics) , physics , linguistics , philosophy , weibull distribution
ISO 10995 is the international standard for the reliability testing and archival lifetime prediction of optical media. The standard specifies the testing conditions in terms of the combinations of stress variables—temperature and relative humidity. The periodically collected data from tests are the error rate of the device, and failure is defined as the error rate exceeding a predetermined level. The standard assumes that the projected failure time is the actual failure time, and these projected failure times are then analyzed by using an Eyring or Arrhenius model. Since true failure times are often not directly observed, the uncertainties in the failure time must be taken into account. In this paper, we present a hierarchical model for degradation that can directly infer failure time at the use condition and compare this model with the International Standard Organization (ISO) standard through a simulation study. Not accounting for the uncertainty in the projected failure times leads to unjustified confidence in the estimation for the median lifetime at both the stress conditions used in the experiments and at the use condition.