Title: Bulge and Dome Testing to Investigate the Formability of Continuous and Stretch Broken Carbon Fiber Prepreg Laminates

Authors: Yoni Shchemelinin, Jared W. Nelson, Cecily Ryan, Dilpreet Bajwa, Doug Cairns, Roberta Amendola

DOI: 10.33599/nasampe/c.22.0158

Abstract: The use of carbon fiber reinforced polymer composites has increased with the increased need for high-strength, low-density materials, particularly in the aviation industry. Stretch broken carbon fiber (SBCF) is a form of carbon fiber created by the randomized breaking of aligned fibers in a tow at inherent flaw points, resulting in collimated fiber fragments longer than chopped fibers. While continuous carbon fibers possess desirable material properties, their limited formability prevents a wider adoption. SBCF composites exhibit pseudo-plastic deformation that can potentially enable the use of traditional metal forming techniques like stamping and press forming well established in mass production applications. To test this hypothesis, bulge and dome testing were performed on quasi-isotropic 8-layer prepreg samples prepared with either continuous or stretch broken Hexcel IM-7 12K fiber, and impregnated with Huntsman RDM 2019-053 resin, to explore the strain behavior under biaxial stress conditions at elevated temperature and atmospheric pressure. The SBCF samples demonstrated larger strain under lower peak pressures than required to form continuous samples. The failure mode was also investigated and found to be similar to metals for SBCF samples. Overall SBCF showed improved formability when compared to continuous fibers. Various formability variables (e.g. forming ratio and forming depth) will be introduced and compared to support SBCF improved formability under different testing conditions.

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Conference: CAMX 2022

Publication Date: 2022/10/17

SKU: TP22-0000000158

Pages: 14

Price: $28.00