STP745

    Specimen Size Effects in Fracture Toughness Testing of Heterogeneous Ceramics by the Notch Beam Method

    Published: Jan 1981


      Format Pages Price  
    PDF Version (136K) 9 $25   ADD TO CART
    Complete Source PDF (4.5M) 9 $55   ADD TO CART


    Abstract

    The variation of apparent KIc with crack length is being studied using a variety of commercial ceramic materials. Test methodology is much the same as has been used in the past for natural rock (notched bend test). Where sufficiently definitive data have been obtained, each material showed decreasing KIc with decreasing crack length with all values falling below KIc determined using constant K specimens (double torsion or constant-moment-arm tests).

    Included in the study was soda-lime glass because it was anticipated that no size effect would occur. Large variations (a factor of two) did occur, however, differing in that all values were above constant K specimen KIc. Post-mortem fracture surface examination revealed problems that can occur where a specimen-wide sharp crack is not achieved before testing.

    Keywords:

    ceramics, fracture toughness, notch bend test, microcracking, composite materials, crack propagation


    Author Information:

    McKinney, KR
    Research physicist and head, Ceramics Branch, Naval Research Laboratory, Washington, D.C.,

    Rice, RW
    Research physicist and head, Ceramics Branch, Naval Research Laboratory, Washington, D.C.,


    Paper ID: STP28301S

    Committee/Subcommittee: E08.08

    DOI: 10.1520/STP28301S


    CrossRef ASTM International is a member of CrossRef.