The foreign object damage (FOD) on leading edge geometries from particles ingested into gas turbine engines found to be comprised of geometric discontinuities like a notch, the residual stresses in regions adjacent to the notch, and material degradation in the form of micro-cracks, plastic deformation, voids, etc. The extent of the damage is related to the geometry and characteristics of the impacting object as well as those of the leading edge in terms of the resultant high cycle fatigue (HCF) strength of a simulated airfoil geometry. Steel spheres having diameters ranging from 0.5 to 2.0 mm are used as the impacting objects at velocities over a range from 60 to 500 m/s. The role of residual stresses is identified through the use of samples subjected to stress relief annealing. Simple notch analysis is used to estimate the effect of the geometry on the fatigue strength. Step-loading fatigue tests in tension-tension at 350 Hz are used to establish the HCF strength corresponding to 107 cycles. Impacts that result in the formation of craters are found to absorb more energy than those that produce chipped or fractured notches of the same geometry. Chipping, on the other hand, is found to be more detrimental to the HCF strength. Simple notch analysis is used to predict crater dimensions, but is found to be applicable only under limited conditions when residual stresses and material damage are not significant. Published by Elsevier Ltd.


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    Title :

    High cycle fatigue limit stresses for airfoils subjected to foreign object damage


    Contributors:
    Ruschau, J. (author) / Thompson, S.R. (author) / Nicholas, T. (author)


    Publication date :

    2003


    Size :

    8 Seiten, 14 Quellen




    Type of media :

    Conference paper


    Type of material :

    Print


    Language :

    English