STP791

    Total Fatigue Life Calculations in Notched SAE 0030 Cast Steel Under Variable Loading Spectra

    Published: Jan 1983


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    Abstract

    A method of fatigue life calculation based upon low-cycle fatigue and fracture mechanics concepts is presented. Two arbitrary crack initiation criteria were analyzed regarding experimental results with SAE 0030 cast steel and theoretical solutions proposed by other authors. Four different load histories based upon the Society of Automotive Engineers (SAE) transmission history using a keyhole compact specimen with two different notch diameters were analyzed. The results showed that the criterion Δa = 0.25 mm (0.01 in.) for crack initiation is practical. However, the exact value of crack length at initiation is not of the greatest importance in total fatigue life calculations. Similarly, fatigue crack growth retardation was not as important as that found with other spectra discussed in the literature. It was found that proper modeling of fatigue crack growth near notches can improve fatigue life calculations. With the present state of knowledge it was possible to calculate the total life within a factor of two. The calculation methods developed primarily for wrought metals were quite acceptable for this cast steel.

    Keywords:

    fatigue (materials), notches, cracks, low cycle fatigue, fracture mechanics, linear elastic fracture mechanics, crack initiation, crack growth, spectra loading, overloads, cast steel


    Author Information:

    Glinka, G
    Faculty, Warsaw Technical University, Warsaw,

    Stephens, RI
    Professor, Materials Engineering Division, The University of Iowa, Iowa City, Iowa


    Paper ID: STP37086S

    Committee/Subcommittee: E08.08

    DOI: 10.1520/STP37086S


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