Fatigue Crack Growth Analyses of Aerospace Threaded Fasteners—Part I: State-of-Practice Bolt Crack Growth Analyses Methods

    Volume 4, Issue 2 (February 2007)

    ISSN: 1546-962X

    CODEN: JAIOAD

    Published Online: 1 March 2007

    Page Count: 16


    Olsen, Kirk W.
    Senior Engineering Specialist, LORD Corporation, Erie, PA

    (Received 3 December 2004; accepted 14 November 2006)

    Abstract

    To perform accurate crack growth analyses on roll-threaded fasteners, aerospace designers are required to estimate fatigue crack growth in the threads of a nut-loaded, roll-threaded bolt under tensile fatigue conditions. Threaded fasteners are difficult to analyze due to their asymmetrical geometry and fastener fatigue crack growth data are scant, especially for nondimensionalized crack depths of (a/d)<0.1. Thus, aerospace designers must make simplifying assumptions and perform analyses with presumably conservative methods. History has shown that improper design assumptions/methods on other critical aircraft components has led to catastrophic failures. Because many fasteners are flight safety critical, their analyses must be accurate. Five leading methods to determine the stress intensity multiplication factor, Y(a/d), for threaded fasteners, based on experimental data, analytic equations, or FE methods, or a combination there of, are compared. By comparing and considering these five methods together, critical observations are made to guide future research based on these state-of-practice Y(a/d) solution methods.


    Paper ID: JAI100491

    DOI: 10.1520/JAI100491

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    Author
    Title Fatigue Crack Growth Analyses of Aerospace Threaded Fasteners—Part I: State-of-Practice Bolt Crack Growth Analyses Methods
    Symposium Structural Integrity of Fasteners Including the Effects of Environment and Stress Corrosion Cracking, 2004-11-10
    Committee E08