STP995V1

    A Numerical Study of Non-Steady-State Creep at Stationary Crack Tips

    Published: Jan 1988


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    Abstract

    A finite-element creep analysis of a center-crack specimen was carried out under small-scale to extensive creep conditions. The crack was assumed to be stationary. Two constitutive models were used, one consisting of elastic-power-law creep and the other of elastic-power-law creep plus rate-independent power-law strain hardening. The mechanics basis of the Ct parameters, which has been proposed for correlating creep crack growth behavior under conditions ranging from small-scale to extensive creep, is explored. Also, an earlier discrepancy in this test specimen between analytically predicted deflection rates and experimental results is investigated. The authors conclude that in small-scale creep, Ct does not characterize the instantaneous crack-tip singular stress field, but accurately reflects the compliance change due to the development of the creep zone around the crack tip. The experimental results, which show higher displacement rates than predicted, cannot be explained by inclusion of time- and rate-independent plasticity but may possibly be due to primary creep.

    Keywords:

    creep, creep crack growth, Ct, parameter, C, *, parameter, fracture mechanics, nonlinear fracture mechanics


    Author Information:

    Leung, C-P
    Graduate research assistant and associate professor, George W. Woodruff School of Mechanical Engineering,,

    McDowell, DL
    Graduate research assistant and associate professor, George W. Woodruff School of Mechanical Engineering,,

    Saxena, A
    Professor, School of Materials Engineering,,


    Paper ID: STP26770S

    Committee/Subcommittee: E08.06

    DOI: 10.1520/STP26770S


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