Dynamic mode II delamination fracture of unidirectional graphite/epoxy composites

• Published in: Composites. Part B, Engineering Vol. 34; no. 3; pp. 303 - 316
• Main Authors: Nwosu, Sylvanus N, Hui, David, Dutta, Piyush K
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.01.2003; Elsevier
• Subjects: Applied sciences; Dynamic delamination; Dynamic fracture mode; Energy absorbed; Energy release rate; Exact sciences and technology; Forms of application and semi-finished materials; Laminates; Polymer industry, paints, wood; Split Hopkinson pressure bar; Technology of polymers; Dynamic delamination; Energy release rate; Split Hopkinson pressure bar; Energy absorbed; Dynamic fracture mode; Notched test piece; Laminate; Unidirectional fiber material; Fiber reinforced material; Mechanical properties; Epoxy resin; Experimental study; Composite material; Fracture toughness; Fracture mechanics test; Measurement method; Delamination; Fracture mode; Damaging; Carbon fiber
• ISSN: 1359-8368; 1879-1069
• DOI: 10.1016/S1359-8368(02)00039-2

Dynamic fracture and delamination of unidirectional graphite/epoxy composites are investigated for end-notched flexure (ENF) and center-notched flexure (CNF) pure mode II loading configurations using a modified split Hopkinson pressure bar. Results show that delamination and energy absorbed in fracture increase with impact energy with CNF>ENF. A power law analytical model reasonably describes the variation of energy release rate with delamination and energy absorbed. A crack embedded deeper in a specimen (as in CNF) contributes more to dynamic fragmentation than cracks at the surface or near the edge (as in ENF). Hackle features on mode II fracture surfaces decrease with impact energy.