STP327: Single-End Glass Yarn Tension Test

    Pirzadeh, Nozar
    The Boeing Co., Aerospace Division, Seattle, Wash.

    Kennedy, Paul B.
    The Boeing Co., Aerospace Division, Seattle, Wash.

    Pages: 13    Published: Jan 1963


    Abstract

    Current tests for evaluating glass reinforcements for filament winding are either unwieldly, inaccurate, or include many of the effects of processing the specimen. Development of a test method for evaluating single-end glass yarn which would be relatively simple, accurate, and eliminate the effects of many of the processing variables common with other types of specimens was undertaken.

    Tests of yarn impregnated with an epoxy resin were found to be more meaningful than tests of unimpregnated yarn and were used throughout the work. The major process conditions of initial cure temperature of the impregnant, tension during cure, resin content, specimen length, and twist of the yarn as received, were found to have little or no effect on the results. The method is sensitive to the elastic moduli and elongation properties of resins, with more flexible, higher elongation materials giving higher strengths. Glass stresses increased with increasing strain rates. Different glass materials affect the results as expected with conventional E glass giving average stresses as high as 386,000 psi and an experimental glass giving an average of 640,000 psi with the same resin system. A direct comparison with a conventional split-disk hoop tension test shows the single-end test to give higher glass stresses but the hoop test appears to have a lower within-group variability.

    The test method presented meets the objectives of simplicity and accuracy and appears suitable for quality control and evaluation purposes.


    Paper ID: STP44431S

    Committee/Subcommittee: D20.94

    DOI: 10.1520/STP44431S


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