Deformation and failure of pseudo-ductile quasi-isotropic all-carbon hybrid FRPS with an open hole under tension

An experimental study has been carried out to investigate the elastic and pseudo-ductile deformation processes of carbon fibre reinforced plastics, containing low elongation (LE) and high elongation (HE) layers of standard thickness. The behaviour of unidirectional homogeneous LE-and HE-laminates, hybrid [HE/LE/HE] and quasi-isotropic composites, with sublaminates sequence [0/45/90/-45]s and [0/60/-60]s were studied up to complete tensile failure. Tests carried out on standard prismatic specimens and specimens with a central hole. A clip-on extensometer and digital image correlation (DIC) were used to distinguish the stable elastic deformation, the microdamage accumulation in the LE-layers, and the delamination of LE and HE layers. For notched specimens, acoustic emission signals revealed the accumulation of scattered microdamage and the localisation of the pseudo-ductility around the hole. The quasi-isotropic hybrid laminates were almost notch insensitive, with the notch sensitivity factors in the open hole tension test for pseudo-yield and ultimate stress below 1.15.

Automated summary

An experimental study was conducted to investigate the elastic and pseudo-ductile deformation processes of carbon fibre reinforced plastics with low elongation (LE) and high elongation (HE) layers. The study examined the stable elastic deformation, microdamage accumulation, and delamination of the LE and HE layers. The results showed that the quasi-isotropic hybrid laminates exhibited good performance in terms of notch sensitivity.