Statistical uncertainty in the fatigue threshold staircase test method

Kim Wallin (Corresponding Author)

    Research output: Contribution to journalArticleScientificpeer-review

    10 Citations (Scopus)

    Abstract

    A popular method of estimating a materials fatigue threshold is the so called staircase test, where a relatively small number of test specimens are used to estimate the materials fatigue strength. Usually the test results are analysed using the maximum likelihood method (MML), either directly or by using the approximation by Dixon and Mood. There has been several studies looking at the bias and confidence of both the mean estimate as well as the standard deviation, but a comprehensive study of the reliability of the estimate has been missing. Here, the accuracy of the MML estimate is studied in detail. It is shown that the MML method is not suitable to estimate the scatter of the fatigue strength from a staircase test. An optional analysis method allowing for a better estimate of confidence bounds, based on binomial probability is presented. Even this new analysis method suffers from similar problems as the MML estimate. The conclusion is that the staircase test cannot be used to estimate the scatter in fatigue strength.
    Original languageEnglish
    Pages (from-to)354-362
    Number of pages9
    JournalInternational Journal of Fatigue
    Volume33
    Issue number3
    DOIs
    Publication statusPublished - 2011
    MoE publication typeA1 Journal article-refereed

    Fingerprint

    Fatigue
    Maximum likelihood
    Fatigue of materials
    Uncertainty
    Maximum Likelihood Method
    Fatigue Strength
    Estimate
    Scatter
    Confidence Bounds
    Mood
    Standard deviation
    Confidence
    Fatigue strength
    Approximation

    Keywords

    • Staircase test
    • fatigue
    • threshold stress
    • maximum likelihood
    • binomial probability

    Cite this

    @article{c2c5d788215f41f182b4777990305e24,
    title = "Statistical uncertainty in the fatigue threshold staircase test method",
    abstract = "A popular method of estimating a materials fatigue threshold is the so called staircase test, where a relatively small number of test specimens are used to estimate the materials fatigue strength. Usually the test results are analysed using the maximum likelihood method (MML), either directly or by using the approximation by Dixon and Mood. There has been several studies looking at the bias and confidence of both the mean estimate as well as the standard deviation, but a comprehensive study of the reliability of the estimate has been missing. Here, the accuracy of the MML estimate is studied in detail. It is shown that the MML method is not suitable to estimate the scatter of the fatigue strength from a staircase test. An optional analysis method allowing for a better estimate of confidence bounds, based on binomial probability is presented. Even this new analysis method suffers from similar problems as the MML estimate. The conclusion is that the staircase test cannot be used to estimate the scatter in fatigue strength.",
    keywords = "Staircase test, fatigue, threshold stress, maximum likelihood, binomial probability",
    author = "Kim Wallin",
    year = "2011",
    doi = "10.1016/j.ijfatigue.2010.09.013",
    language = "English",
    volume = "33",
    pages = "354--362",
    journal = "International Journal of Fatigue",
    issn = "0142-1123",
    publisher = "Elsevier",
    number = "3",

    }

    Statistical uncertainty in the fatigue threshold staircase test method. / Wallin, Kim (Corresponding Author).

    In: International Journal of Fatigue, Vol. 33, No. 3, 2011, p. 354-362.

    Research output: Contribution to journalArticleScientificpeer-review

    TY - JOUR

    T1 - Statistical uncertainty in the fatigue threshold staircase test method

    AU - Wallin, Kim

    PY - 2011

    Y1 - 2011

    N2 - A popular method of estimating a materials fatigue threshold is the so called staircase test, where a relatively small number of test specimens are used to estimate the materials fatigue strength. Usually the test results are analysed using the maximum likelihood method (MML), either directly or by using the approximation by Dixon and Mood. There has been several studies looking at the bias and confidence of both the mean estimate as well as the standard deviation, but a comprehensive study of the reliability of the estimate has been missing. Here, the accuracy of the MML estimate is studied in detail. It is shown that the MML method is not suitable to estimate the scatter of the fatigue strength from a staircase test. An optional analysis method allowing for a better estimate of confidence bounds, based on binomial probability is presented. Even this new analysis method suffers from similar problems as the MML estimate. The conclusion is that the staircase test cannot be used to estimate the scatter in fatigue strength.

    AB - A popular method of estimating a materials fatigue threshold is the so called staircase test, where a relatively small number of test specimens are used to estimate the materials fatigue strength. Usually the test results are analysed using the maximum likelihood method (MML), either directly or by using the approximation by Dixon and Mood. There has been several studies looking at the bias and confidence of both the mean estimate as well as the standard deviation, but a comprehensive study of the reliability of the estimate has been missing. Here, the accuracy of the MML estimate is studied in detail. It is shown that the MML method is not suitable to estimate the scatter of the fatigue strength from a staircase test. An optional analysis method allowing for a better estimate of confidence bounds, based on binomial probability is presented. Even this new analysis method suffers from similar problems as the MML estimate. The conclusion is that the staircase test cannot be used to estimate the scatter in fatigue strength.

    KW - Staircase test

    KW - fatigue

    KW - threshold stress

    KW - maximum likelihood

    KW - binomial probability

    U2 - 10.1016/j.ijfatigue.2010.09.013

    DO - 10.1016/j.ijfatigue.2010.09.013

    M3 - Article

    VL - 33

    SP - 354

    EP - 362

    JO - International Journal of Fatigue

    JF - International Journal of Fatigue

    SN - 0142-1123

    IS - 3

    ER -