Adhesive bonding of discontinuous carbon fibre composites: an experimental investigation

The excellent specific stiffness and strength of carbon fibre reinforced polymer composites means that the automotive sector has been investigating methods of implementing these materials into structurally demanding applications. The work detailed within this thesis supports ongoing research at the University of Nottingham into the automated manufacture of discontinuous carbon fibre reinforced polymer composite materials. Advances in the automation of composites manufacturing has meant that methods to effectively join these materials is required. This work provides a fundamental understanding of the differences that result from the adhesive bonding of a discontinuous fibre composite (DFC) compared to conventional fibre reinforced composite materials. The main objective of the project was to characterise the behaviour of adhesively bonded DFC adherends. Using a single lap shear joint geometry, an optimised fibre architecture and joint geometry was identified with a 2-part low temperature curing epoxy adhesive being characterised for industrial application. To further improve the performance of the DFC substrates, a fibre alignment technique was implemented that achieved properties comparable to those of more traditional non-crimp fabric composites. From the experimental investigations conducted, the use of discontinuous carbon fibre reinforced composites in bonded assemblies shows promise with the potential for use in structural applications