Transverse impact on a single layer S-glass/Sc15 epoxy composite strip

Insight into ballistic impact resistance of fiber reinforced polymer composite (FRPC) strip provides detailed material damage information by isolating and investigating materials from a whole composite laminate. In this work, transverse impact experiments on single-layer S-Glass fiber/SC15 epoxy composite strips by Right Circular Cylinders (RCC) were performed. The critical velocity, essentially dividing two phenomenological phases, penetration and perforation, respectively, was obtained as 274-409 m/s after multiple shootings with different velocities. The real-time mechanical behavior of each composite strip was captured by a high-speed camera. Post-fracture images were gained by a Scanning Electronic Microscope (SEM), providing further information about failure surfaces of the fiber and matrix. Experiments show that the composite strip failed in a tent-like shape with obvious matrix failure and fiber/matrix interfacial debonding under below-critical-velocity impact. When the projectile velocity exceeded the critical velocity, materials ruptured instantly at the projectile front without wave propagating to the two ends, which indicates the loss of energy dissipation capability of the composite. An obvious transition phase, when the projectile impacted the strip in the critical velocity, was observed with part of the composite strip failing locally in transverse direction and the residual part forming a tent-like shape and being tensioned until break.