Mechanisms and characterization of impact damage in 2D and 3D woven fiber-reinforced composites

Low velocity impact damage of 2D and 3D woven glass/epoxy composites with the same areal density and material constituents were examined. Characterization of damage for both plate and beam sample geometries was investigated through the collection of high-resolution cross-sectional images after impact. Load and displacement data collected during impact testing reveals that the threshold load to introduce delamination damage is independent of the fabric architecture and is constant across a range of impact energies. Delamination length and opening of 3D woven composites was less than 2D composites impacted at the same energy as a result of suppression of delamination propagation and opening offered by the Z-tow reinforcement of the 3D fabric architecture. The formation of transverse shear cracks was independent of the fabric architecture.