Abstract
Progressive crushing tests of unidirectionally laminated carbon fiber reinforced plastic (CFRP) rectangular plate were carried out to reveal its continuous fracture behavior and energy absorption. A special test fixture was developed for the test and fracture process of the CFRP was observed from its side section. Three types of trigger geometries, i.e. chamfer, steeple and V-shape trigger, were machined on each specimen. Film embedded V-shape trigger was also prepared to investigate the effect of initial cracks on energy absorption. The initial fracture behavior strongly affected the ensuing stable fracture process. It was clarified that V-shape trigger specimen was robust over the variation of gage length (unsupported length) as compared to chamfer and steeple trigger specimen which showed smaller energy absorption with longer gage length. A column-like part, which was called pillar in this paper, was observed between fronds under crushing. The fracture was much severe at pillar section than fronds section. Fiber fractures were observed periodically at 50-100 μm length in the pillar section, which coincides with the length of kink band in ultimate compressive failures of CFRP. It was revealed that the thickness of pillar was dominant factor on energy absorption of unidirectional CFRP.
