Strain and Damage-Based Analytical Methods to Determine the Kachanov-Rabotnov Tertiary Creep-Damage Constants

    Authors

    C. M. Stewart;A. P. Gordon

    Comments

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    Abbreviated Journal Title

    Int. J. Damage Mech.

    Keywords

    continuum damage mechanics; constant determination; Kachanov-Rabotnov; master curve; Ni-base superalloys; Norton's power law; rupture; prediction; stress-independent; Waspaloy; STRESS; STATES; Materials Science, Multidisciplinary; Mechanics

    Abstract

    In the power generation industry, the goal of increased gas turbine efficiency has led to increased operating temperatures and pressures necessitating nickel-base superalloy components. Under these conditions, the tertiary creep regime can become the dominant form of creep deformation. In response, the classical Kachanov-Rabotnov coupled creep-damage constitutive model is often used to predict the creep deformation and damage of Ni-base superalloys. In this model, the secondary creep behavior can be determined through analytical methods while the tertiary creep behavior is often found using trial and error or numerical optimization. Trial and error may produce no constants. Numerical optimization can be computationally expensive. In this study, a strain-based and damage-based approach to determine the tertiary creep behavior of nickel-base superalloys has been developed. Analytically determined constants are found for a given nickel-base superalloy. Creep deformation and damage evolution curves are compared. Methods to deal with stress dependence are introduced and studied.

    Journal Title

    International Journal of Damage Mechanics

    Volume

    21

    Issue/Number

    8

    Publication Date

    1-1-2012

    Document Type

    Article

    Language

    English

    First Page

    1186

    Last Page

    1201

    WOS Identifier

    WOS:000309937900004

    ISSN

    1056-7895

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