STP677

    Effect of Specimen Geometry on Crack Growth Resistance

    Published: Jan 1979


      Format Pages Price  
    PDF Version (272K) 22 $25   ADD TO CART
    Complete Source PDF (12M) 22 $224   ADD TO CART


    Abstract

    The crack growth resistance of 20 mm thick (complying with American Petroleum Institute 5LX65 specifications pipeline steel) in the longitudinal orientation has been measured employing the yielding mechanics parameters J and crack opening displacements (COD) on the three-point bend and center-cracked tension specimen configurations.

    The values of these parameters at the initiation of cracking for the two geometries were essentially identical. The resistance curve derived for the tension geometry, however, was appreciably steeper than its bend counterpart.

    A comparison of J estimation methods is presented and a simple relationships suggested for the determination of COD resistance for the center-cracked tension geometry.

    Energy balance considerations are extended to describe instability in the elastic-plastic regime and J driving force curves estimated for the three-point bend and center-cracked tension geometries.

    In addition, the analysis was employed to derive the Paris instability parameter T and the results compared with the existing formulations.

    Keywords:

    fracture strength, toughness, crack resistance, crack initiation, crack propagation, geometry, instability, low alloy steels, fatigue (materials)


    Author Information:

    Garwood, SJ
    Senior research engineer, The Welding Institute, Abington, Cambridge


    Paper ID: STP34933S

    Committee/Subcommittee: E08.06

    DOI: 10.1520/STP34933S


    CrossRef ASTM International is a member of CrossRef.