Aging property of unimodal failure rate models

R. Jiang, Ping Ji, X. Xiao

Research output: Journal article publicationJournal articleAcademic researchpeer-review

98 Citations (Scopus)


There is a family of statistical models, whose failure rate is unimodal or reverse bathtub shaped. For the situations where the failure is mainly caused by fatigue or corrosion, the time to failure is often represented by such models. This paper studies the aging property of such a class of models. It shows that a unimodal failure rate can be effectively viewed as increasing, decreasing, or constant, depending on the model parameters. Relevant quantitative measures are developed to identify to which case a given unimodal failure rate model belongs. Such two models, lognormal and inverse Weibull distributions, are analyzed.
Original languageEnglish
Pages (from-to)113-116
Number of pages4
JournalReliability Engineering and System Safety
Issue number1
Publication statusPublished - 1 Jan 2003


  • Average aging intensity
  • Failure rate
  • Relative peakedness
  • Reverse bathtub curve

ASJC Scopus subject areas

  • Safety, Risk, Reliability and Quality
  • Industrial and Manufacturing Engineering


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