STP1439: Fatigue Design and Experimentations with Variable Amplitude Loadings in the Automotive Industry

    Thomas, JJ
    PSA Peugeot Citroën, Vélizy Villacoublay,

    Bignonnet, A
    PSA Peugeot Citroën, Vélizy Villacoublay,

    Perroud, G
    PSA Peugeot Citroën, Vélizy Villacoublay,

    Pages: 14    Published: Jan 2005


    The paper presented gives an overview of the various problems that should be addressed to take into account the variable amplitude loadings undergone by the car components. One of the most important point is that all the steps of the design procedure (including experiments and computations) should be consistent with each other in terms of damage. For some reasons (efficiency, robustness, capitalization,…), variable amplitude loading may be converted into damage equivalent loadings. Tools such as cycle counting ,damage summation including the mean value effect and rainflow extrapolation are therefore necessary. The paper shows how single component and full scale tests are related with both customer and test track measurements, and how these experimental data are correlated with predictive fatigue computations, including the statistical aspects for reliability purpose. The paper will illustrate that if the consistency mentioned above is guaranteed, then the variable amplitude fatigue computation (such as the ones proposed in commercial codes) is no longer useful. It requires therefore an analysis of the material behavior under variable amplitude loadings in the automotive context. One of the most important advantage of this approach is that under simple assumptions, the computations can be realized before any prototype could be driven on a track. It allows to shorten the developments delays. These assessments will be illustrated by various examples showing how the loadings are analyzed in the measurements stages, and how they are applied in the experimental and computation stages.


    Stress-strength interference analysis, variable amplitude, fatigue, automotive

    Paper ID: STP11317S

    Committee/Subcommittee: E08.05

    DOI: 10.1520/STP11317S

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