Tiny yet tough: Maximizing the toughness of fiber-reinforced soft composites in the absence of a fiber-fracture mechanism

The toughness of composite materials is size dependent below a critical load transfer length (lT). Fiber-reinforced viscoelastic polymers are uniquely suited to study the size-limited regime because lT these soft composites can be as high several centimeters, in contrast traditional where extremely small, allowing large window for macroscale characterization. In this work, we elucidate parameters that influence when failure governed by fiber pullout-induced matrix-fracture mechanism. We ultimately demonstrate three important points: (1) fiber-reinforced possess toughness, even at dimensions well lT, (2) significant amplification occurs due presence fibers, fracture process consists solely matrix rupture, and (3) pullout region predicted from easily attainable component parameters.