Effect of Environment on Fracture Toughness and Debond Growth of Aluminum/FM®73/Boron-Epoxy Adhesively Bonded Joints

    Volume 23, Issue 1 (January 2001)

    ISSN: 0884-6804

    CODEN: CTROAD

    Page Count: 8


    Lubke, KA
    Ford Corporation,

    Butkus, LM
    Major in USAF at Wright Patterson AFB, OH

    Johnson, WS
    Professor, Georgia Institute of Technology, Atlanta, GA

    (Received 14 September 1999; accepted 31 October 2000)

    Abstract

    Tests were conducted to determine the fracture toughness of aluminum/FM®73/boron-epoxy adhesively bonded joints. Double cantilever beam (DCB) specimens and end-notched flexure (ENF) specimens were exposed to one of the following environments: hot/wet (71° C(160° F) and >90% RH) conditions for 5000 h, thermal cycles between 71° C (160° F) and −54° C (−65° F), or an outdoor “rooftop” environment for 10 000 h. The environmentally exposed specimens were tested along with as-received (or unexposed specimens). The different adherend materials had different coefficients of thermal expansion (CTE). The mismatch of CTE between adherends caused residual thermal stresses in the adhesive joints at every temperature other than the elevated cure temperature. The residual stresses could not be accounted for with closed form solutions. Finite element analysis (FEA) of the specimens was required. Using FEA solutions, it was determined that the fracture toughness of the environmentally exposed specimens was lower than the as-received specimens for every environment tested for both DCB and ENF specimens.


    Paper ID: CTR10912J

    DOI: 10.1520/CTR10912J

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    Author
    Title Effect of Environment on Fracture Toughness and Debond Growth of Aluminum/FM®73/Boron-Epoxy Adhesively Bonded Joints
    Symposium , 0000-00-00
    Committee D30