STP1206

    Evaluation of Compression Specimens and Fixtures for Testing Unidirectional Composite Laminates

    Published: Jan 1993


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    Abstract

    This two-part study consisting of analysis and experimentation was used to evaluate six fixtures and the corresponding specimens. The stress state in each specimen was determined using the finite element technique. In the experimental portion of this study, specimens corresponding to each of the six fixtures were cut from [0°]16 panels fabricated from a graphite/epoxy (AS4/3501-6) material system and tested. The results of this analytical/experimental study indicate that the test techniques that incorporate side support plates to prevent buckling of end-loaded specimens provide an inaccurate measure of compressive strength and their use should be discontinued. Among the shear loaded specimens, the performance of the IITRI fixture was determined to be inadequate due to a nonuniform state of stress in the test section and it was improved significantly by the use of Sendeckyj-Rolfes specimen. The Celanese fixture yielded good results except that the specimen was so narrow that it was difficult to instrument and test. It was determined that in terms of average compressive failure strength and uniformity of stress in the test section, the Rolfes fixture using the Sendeckyj-Rolfes specimen outperformed the other five fixtures/specimens tested.

    Keywords:

    composite materials, compression specimen, finite element analysis, compression fixtures, compression testing


    Author Information:

    Daniels, JA
    Captain, USAF, HQ/AFMC(STXP), Wright Patterson Air Force Base, OH

    Sandhu, RS
    Aerospace engineer, Wright Laboratory; Wright Patterson Air Force Base, OH


    Paper ID: STP12622S

    Committee/Subcommittee: D30.04

    DOI: 10.1520/STP12622S


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