SYMPOSIA PAPER Published: 01 January 1997

Static and Fatigue Interlaminar Tensile Characterization of Laminated Composites


Spool and curved-beam specimens were evaluated to determine the viability of using either one or both of these configurations to characterize the static and fatigue interlaminar tensile behavior of carbon/epoxy laminates. Unidirectional curved-beam and quasi-isotropic spool specimens were fabricated, nondestructively inspected, and statically tested to failure. Tension-tension fatigue tests were conducted at 10 Hz and an R-ratio (σminmax) equal to 0.1 for each specimen configuration. The interlaminar tensile strength of the spool specimen was 12% larger than the strength obtained using curved-beam specimens. In addition, data scatter associated with spool specimens was significantly less than the scatter associated with curvedbeam specimens. The difference in data scatter was attributed to the influence of the fabrication process on the quality of the laminates tested. The fatigue limit at 107 cycles for both specimen types was shown to be at least 40% of the average interlaminar tensile strength. Based on the results of this study, it was concluded that either the spool or the curved-beam specimens can be used to characterize the interlaminar tensile static and fatigue behavior of carbon/epoxy laminates. However, to obtain the most representative results, the test specimen configuration should be selected so that the specimen fabrication process closely simulates the actual component fabrication process.

Author Information

Koudela, KL
Applied Research Laboratory, State College, PA
Strait, LH
Applied Research Laboratory, State College, PA
Caiazzo, AA
Applied Research Laboratory, State College, PA
Gipple, KL
Naval Surface Warfare Center, Bethesda, MD
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Developed by Committee: D30
Pages: 516–530
DOI: 10.1520/STP19945S
ISBN-EB: 978-0-8031-5353-0
ISBN-13: 978-0-8031-2411-0