STP696

    Impact Damage Effects on the Strength of Advanced Composites

    Published: Dec 1979


      Format Pages Price  
    PDF Version (296K) 13 $25   ADD TO CART
    Complete Source PDF (9.0M) 13 $55   ADD TO CART


    Abstract

    This paper discusses the effect of flaws created by impact damage on the strength of graphite/epoxy panels that were tested as sandwich beams and as skin panels on box beams. A majority of the panels were exposed to random spectrum fatigue loads prior to failing them under static loading conditions. The maximum loads in the fatigue spectrum were scaled to provide a strain equal to the B-basis matrix failure strain for the resin system used. Box beam skin panels were designed to fail by compressive panel buckling in order to evaluate the effect of the impact damage on the buckling strength of the panels. All testing was conducted at room temperature on panels with no moisture conditioning.

    Marginally visible damage was found to cause a strength loss up to 35 percent in compression but less in tension. Acoustic C-scan inspections showed that none of the impact damage sizes grew during spectrum loading. Panel stability was unaffected by localized impact damage. The most severe impact damage caused strength losses comparable to drilled fastener holes.

    Keywords:

    graphite/epoxy, composite materials, impact damage, strength testing, nondestructive tests


    Author Information:

    Labor, JD
    Senior technical specialist, Northrop Corp., Aircraft Group, Hawthorne, Calif


    Paper ID: STP36031S

    Committee/Subcommittee: D30.02

    DOI: 10.1520/STP36031S


    CrossRef ASTM International is a member of CrossRef.