STP942

    Effect of Superimposed Stresses at High Frequency on Low Cycle Fatigue

    Published: Jan 1988


      Format Pages Price  
    PDF Version (444K) 23 $25   ADD TO CART
    Complete Source PDF (27M) 23 $271   ADD TO CART


    Abstract

    The effects of superimposed stresses at high frequency on low cycle fatigue behavior were studied on two aeronautical alloys (Ti 6-4 and Inconel 718) in terms of crack initiation, crack propagation, and failure. It is shown that, if the minor cycles have limited amplitudes, not more than 10 to 15% of low cycle fatigue stresses, the life is monitored by the maximum stress of the cycles. This is correlated with the fact that, in this case, the endurance limit of the material is not exceeded. The same criterion is suitable for crack initiation of Inconel 718, but not for Ti 6-4 which is, in all cases, much more sensitive to mixed fatigue than Inconel 718.

    The crack propagation regime is ruled by minor cycles only beyond an observed transition ΔK value. For both materials, linear cumulation rules are inadequate for predicting the number of cycles to failure and for calculating the crack growth rates in mixed fatigue.

    Keywords:

    low cycle fatigue, high cycle fatigue, mixed fatigue, crack initiation, crack propagation, titanium base alloy, nickel base alloy, life prediction


    Author Information:

    J-Y, Guedou
    SNECMA, Evry CEDEX,

    J-M, Rongvaux
    SNECMA, Evry CEDEX,


    Paper ID: STP24533S

    Committee/Subcommittee: E08.05

    DOI: 10.1520/STP24533S


    CrossRef ASTM International is a member of CrossRef.