Enhanced delamination initiation stress and monitoring sensitivity of quasi-isotropic laminates under in-plane tension by interleaving with CNT buckypaper

Delamination initiation and the corresponding in-situ monitoring method have been investigated for a T300/epoxy quasi-isotropic laminate. Interfaces of the laminate, in which the delamination tends to occur under in-plane tensile load, have been interleaved with porous carbon nanotube (CNT) buckypapers. Both sectional loading to the delamination initiation and full tension to the fracture of specimens were performed to evaluate the reinforced effect and self-sensing properties of the CNT buckypapers on the laminates. As expected, enhanced delamination initiation stress level was obtained, improved by 7.7% compared with that of the base laminate. Simultaneously, electrical resistance and acoustic emission (AE) responses of the laminates were also measured and used to determine the initiation of delamination. The tests have exhibited that the CNT buckypapers have significant influence on the resistance change of the laminate, showing potential to be used as a detector. This study has preliminarily demonstrated that the CNT buckypapers can serve as both sensing and strengthening constituent.