Methods of modifying through-thickness electrical conductivity of CFRP for use in structural health monitoring, and its effect on mechanical properties – A review

As the use of carbon fibre reinforced polymers (CFRP) is continuing to increase in engineering applications, more functionalities will be required. Having an enhanced through-thickness electrical conductivity can be a useful functionality for CFRPs which will minimise their damage from lightning strikes, and will help in their real-time monitoring. For most modification methods there is an adverse effect on the manufacturing and the fibre volume fraction, which influence the mechanical properties of the resulting composites. Simultaneous improvement of multiple properties of CFRPs is difficult, and as such the ways in which different materials and processes improve properties of CFRPs need to be understood in depth. This review discusses research that attempts to improve the through-thickness electrical conductivity of CFRPs with interest in the effects on mechanical properties, specifically interlaminar fracture toughness. The last section discusses the effect and use of these methods to improve structural health monitoring (SHM) of CFRPs.