STP627

    Fracture Initiation in Metals Under Stress Wave Loading Conditions

    Published: Jan 1977


      Format Pages Price  
    PDF (316K) 18 $25   ADD TO CART
    Complete Source PDF (6.7M) 18 $55   ADD TO CART


    Abstract

    An experimental procedure is described for accurately establishing the dynamic fracture initiation properties of structural metals at extremely high loading rates. The apparatus is an adaptation of the Kolsky pressure bar (split-Hopkinson bar) in which a 1-in.-diameter round bar specimen with a prefatigued circumferential notch is loaded to failure by the rapidly rising tensile pulse resulting from an explosive detonation. Using the standard Kolsky technique, the average stress at the fracture site is measured as a function of time. Crack opening displacement is measured by optical means, as a function of time, thus yielding a complete load-displacement record for each test. From the data the critical value of the crack-tip stress intensity factor, K1c, at loading rates, ˙K1 in excess of 109 psi √in./s may be obtained. This is nearly two orders of magnitude faster than has been achieved by other standard techniques. Results are presented for dynamic tests conducted on SAE 4340 steel and 1020 cold-rolled steel, and these are compared to results from static tests performed on specimens of similar shape.

    Keywords:

    fracture initiation, fracture properties, experimental techniques, explosive loading, stress waves, strain rate, metals


    Author Information:

    Costin, LS
    Research assistant, professor of engineering, and professor, Division of Engineering, Brown University, Providence, R.I.

    Duffy, J
    Research assistant, professor of engineering, and professor, Division of Engineering, Brown University, Providence, R.I.

    Freund, LB
    Research assistant, professor of engineering, and professor, Division of Engineering, Brown University, Providence, R.I.


    Paper ID: STP27395S

    Committee/Subcommittee: E08.04

    DOI: 10.1520/STP27395S


    CrossRef ASTM International is a member of CrossRef.