Finite element simulations and neutron diffraction measurements of the residual stress state in a compressor disc made of IN718 after quenching in water have been performed. The same FEM code, DEFORM, has been employed to simulate the forging process as well as the quenching procedure. The aim of the present study was an experimental verification of the cooling simulation. Especially the evolution of the heat transfer coefficient was of prime importance, because it has a significant influence on the residual stress state after quenching. However, the heat transfer coefficient is the only material input data that can not be measured directly, therefore, parameter studies have been carried out to clarify its influence. Additionally, the temperatures within the disc have been measured at 5 positions during quenching in water. These two independent sets of experimental data indicated an lower and upper bound of 2000 to 5000 W/m(exp2)K for a constant heat transfer coefficient. Although in reality the heat transfer is not constant, but depends on the surface and water temperature, a constant value of 4000 W/m(exp2)K seems to give a good approximation to simulate the evolution of the residual stress state. Allowing the heat transfer coefficient to vary with time or surface temperature offers the possibility of an improved fit of the measured temperatures. Theses changes have an effect also on the maximum stress levels and especially on the shape of the stress gradient. It seems that the heat transfer coefficient can momentarily be much higher than 5000 W/m2K. Temporarily values above 14000 W/m(exp2)K combined with moderate conditions at the beginning and towards the end lead to a better fit of the measured temperature curves. The results suggest that the simulation can be further improved by an adopted temperature dependent heat transfer coefficient. Nevertheless, also a constant value of 4000 W/m(exp2)K leads to a good prediction to the independently measured residual stresses and temperatures.


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    Titel :

    Characterization of residual stresses in compressor discs for aeroengines: neutron diffraction and finite element simulations.


    Weitere Titelangaben:

    Charakterisierung der Restspannungen in Kompressorscheiben für Flugzeugantriebe: Neutronendiffraction und Finite-Elemente-Simulationen


    Beteiligte:
    Cihak, Ulrike (Autor:in) / Stockinger, Martin (Autor:in) / Staron, Peter (Autor:in) / Tockner, Johann (Autor:in) / Clemens, Helmut (Autor:in)


    Erscheinungsdatum :

    2005


    Format / Umfang :

    10 Seiten, 7 Bilder, 2 Tabellen, 19 Quellen


    Medientyp :

    Aufsatz (Konferenz)


    Format :

    Print


    Sprache :

    Englisch





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