SYMPOSIA PAPER Published: 01 January 1992
STP20144S

A Method for Evaluating the High Strain Rate Compressive Properties of Composite Materials

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A test apparatus and method developed to obtain high strain rate compressive mechanical properties of various fiber-reinforced composite materials is described. This direct compressive method uses a drop tower to impart a load at dynamic rates to the test fixture. Uniform specimen loading is accomplished through the use of aligned guiderails to constrain all but the vertical motion of a free-sliding impactor. Specimen endcaps, specific to thick-section testing, are implemented to prevent premature brooming failure. A piezoelectric transducer and aluminum absorbers are some of the refinements introduced to allow acquisition of stress and strain data free of distortion. Strain rates on the order of 8 s-1 have been achieved, and higher rates appear possible. Material property data were obtained on a series of AS4 graphite/PEEK thermoplastic [02/90]8s composite laminates. The results of this first study indicate that at high strain rate loading, the strength of this material increases 42% over static values, while the strain to failure increases by 257#x0025;. There also appears to be a small effect of increased strain rate on the initial and secant moduli for this material.

Author Information

Montiel, DM
Forensic Technologies International, Annapolis, MD
Williams, CJ
Composites and Resins Branch of the David Taylor Research Center, Annapolis, MD
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Details
Developed by Committee: D30
Pages: 54–65
DOI: 10.1520/STP20144S
ISBN-EB: 978-0-8031-5184-0
ISBN-13: 978-0-8031-1426-5