Acceptance sampling plans based
on failure-censored step-stress
accelerated tests for Weibull
Sang Wook Chung and Young Sung Seo
Department of Industrial Engineering, Chonnam National University,
Gwangju, Korea, and
Won Young Yun
Department of Industrial Engineering, Pusan National University,
Purpose – The paper aims to present acceptance sampling plans based on failure-censored
step-stress accelerated life tests for items having Weibull lives.
Design/methodology/approach – The model parameters are estimated by the method of
maximum likelihood. Based on asymptotic distribution theory, the sample size and the
acceptability constant are determined satisfying the producer’s and consumer’s risks. The
step-stress accelerated life test is optimized to have a minimum sample size by minimizing the
asymptotic variance of test statistic. Two modes of step-stress accelerated life test are considered, and
a comparison between them is made. The proposed sampling plans are compared with the sampling
plans based on constant stress accelerated life tests.
Findings – Asymptotic variance is a dominating factor in determining the sample size required for a
sampling plan to determine the acceptability of a lot. The sample size is minimized by optimally
designing a step-stress accelerated life test so that the asymptotic variance is minimized.
Originality/value – The sampling plans presented in this paper are particularly useful when items
to be tested are so reliable and are useful to reliability engineers and life test planners.
Keywords Acceptance sampling, Product design, Product life cycle, Customer satisfaction,
Paper type Research paper
It is essential from the consumer’s point-of-view that a product perform the required
function without failure for the desired period of time. The lifetime of a product is
therefore one of the most important quality characteristics. Life-test sampling plans are
commonly used to determine the acceptability of a product with respect to lifetime.
Much work has been done for the design of the life-test sampling plans. Fertig and
Mann (1980) discussed sampling plans for the Weibull distribution using best linear
invariant estimators. Kocherlakota and Balakrishnan (1986) considered one- and
two-sided sampling plans for the exponential distribution. Schneider (1989) discussed
failure-censored sampling plans for the lognormal and Weibull distributions using
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This study was ﬁnancially supported by Chonnam National University in the program, 2002.
Journal of Quality in Maintenance
Vol. 12 No. 4, 2006
q Emerald Group Publishing Limited