Gauge Length and Temperature Influence on the Tensile Properties of Stretch Broken Carbon Fiber Tows

Abstract Continuous carbon fibers are premium reinforcing material for aerospace composites. The challenge with continuous carbon fibers is their difficulty to form deep drawn parts requiring intricate manufacturing techniques that increase manufacturing time, cost and material waste. Stretch broken carbon fiber (SBCF), is a form of aligned discontinuous fiber, has been proposed as an alternative to overcome this challenge. SBCF provide flexibility to form complex shapes while maintaining comparable strength and stiffness. This study compared the tensile behavior of sized continuous fiber and SBCF tows at seven different gauge lengths and two temperatures (24° C and 100° C). Materials included Hexcel IM7-G continuous carbon fiber and Hexcel IM7-GP SBCF. The results of this study show that SBCF demonstrate decreased tensile loads when tested at elevated temperatures compared to continuous fibers. The maximum load capacity of SBCF tow increases as gauge length decreases. The load bearing capacity of heated SBCF tow is linked to fiber continuity. These findings suggest superior forming properties of SBCF as compared with continuous fiber tow.