STP893

    Effect of Stress Biaxiality on the Transverse Tensile Strain-to-Failure of Composites

    Published: Jan 1986


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    Abstract

    Thermoplastic matrices are now available with neat resin strain-to-failure values of up to 100%. These high strain-to-failure values could be expected to result in dramatically higher transverse strain-to-failure values in thermoplastic composites than epoxy composites. However, measurements of the transverse strain-to-failure of some thermoplastic composites have revealed only a modest increase in transverse strain capability. The objective of this work was to show that the matrix is biaxially stressed in a transverse tension test and that this significantly reduced strain-to-failure values.

    To accomplish this objective, a specimen configuration was designed to introduce biaxial stresses into the neat resin. Data was generated on polyetheretherketone and polycarbonate, both ductile thermoplastics. Test results showed that biaxial stresses reduced the strain-to-failure of these materials by well over an order of magnitude. Thus, this work shows that, while a thermoplastic matrix's ductility may translate into composite toughness and delamination resistance, it does not necessarily translate into dramatically increased composite transverse strain-to-failure values.

    Keywords:

    composite materials, transverse testing, transverse strain-to-failure values, biaxial stresses, thermoplastic, polyetheretherketone, polycarbonate


    Author Information:

    Nicholls, DJ
    Captain, AFA/DFEM, U. S. Air Force Academy, Colorado Springs, CO


    Paper ID: STP35344S

    Committee/Subcommittee: D30.08

    DOI: 10.1520/STP35344S


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