Reduced notch sensitivity in pseudo-ductile CFRP thin ply angle-ply laminates with central 0° plies

This paper presents an experimental investigation on the unnotched and open-hole tensile behaviour of pseudo-ductile thin ply angle-ply carbon fibre/epoxy laminates with central 0° plies. Laminates with two different configurations of [±26₅/0]_s and [±25₂/0]_s were designed and tested under unnotched and open-hole tensile loading. Metal-like tensile stress-strain curves with a plateau were observed in both unnotched configurations. The open-hole net-section strength of the [±25₂/0]_s laminate attained 96% of the unnotched “yield” strength. Digital image correlation and X-ray CT-scan images showed that the same damage mechanisms of central 0° ply fragmentation and local dispersed delamination observed in unnotched pseudo-ductile laminates were present in the open-hole specimens of the same configuration. These damage mechanisms caused stress redistribution around the hole and reduced the notch sensitivity in pseudo-ductile laminates under open-hole tensile loading. The main factors governing the open-hole performance are also discussed.