STP1546: Influence Analysis of Application-Specific Phenomena on the Creep-Fatigue Life of Turbine Housings of Turbochargers

    Laengler, F.
    BorgWarner Turbo Systems Engineering GmbH, Kirchheimbolanden,

    Mao, T.
    Institute for Materials Science, Technical Univ. of Darmstadt, Darmstadt,

    Scholz, A.
    Institute for Materials Science, Technical Univ. of Darmstadt, Darmstadt,

    Pages: 16    Published: Jul 2012


    Abstract

    The turbine housing of a turbocharger is exposed to extensive cyclic thermo-mechanical loading. This leads to multiaxial stress states with local plastifications, so that the design of the turbine housing becomes a major challenge in ensuring the guaranteed lifetime in relation to the high-temperature behavior of the materials. In a first step, a phenomenological lifetime approach in conjunction with a constitutive material model applied in a preceding finite-element analysis was developed and validated for application on the casting materials Ni-resist D5S and vermicular cast iron GJV. The present study deals with the adaption for turbine housing design together with the more detailed analysis of application-specific phenomena to improve the description of both the deformation behavior and the creep-fatigue damage behavior. The influence of different strain rates, mean strain conditions, and aging has been evaluated. Moreover, a critical plane approach has been investigated to handle multiaxial stress and strain states. A more accurate damage ratio is derived by use of specimens subjected to characteristic thermo-mechanical load conditions, which leads to an improved estimation of the cycle number until crack initiation on critical component positions.

    Keywords:

    turbine housing, finite-element analysis, elastoplasticity, thermo-mechanical fatigue, creep-fatigue life assessment, Ni-resist D5S


    Paper ID: STP154620120011

    Committee/Subcommittee: E08.07

    DOI: 10.1520/STP154620120011


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