Progressive crushing behavior and energy absorption of a unidirectional CFRP plate under axial compression

Progressive crushing tests of a unidirectionally laminated carbon fiber-reinforced plastic (CFRP) rectangular plate were carried out to reveal its continuous fracture behavior and energy absorption. Three types of trigger geometry, chamfer, steeple, and V-shaped, were machined on each specimen. A film-embedded V-shaped trigger was also prepared to investigate the effect of initial cracks on the energy absorption. The initial fracture behavior strongly affected the ensuing stable fracture process. The V-shaped trigger specimen was robust as the gauge length varied, in contrast to the chamfer and steeple trigger specimens which absorbed less energy with a longer gauge length. A column-like pillar was observed between the fronds during the crushing. Fiber fractures were observed periodically at 50-100 μm lengths in the pillar section, which coincides with the length of the kink band in CFRP ultimate compressive failures. The pillar thickness was a dominant factor in the energy absorption of unidirectional CFRP.