A review of multiscale composite manufacturing and challenges

As the utilization of advanced composites in structural applications grows, the need for improving their through-thickness properties becomes imperative. Although the behavior of composite laminates under structural and thermal loads has received much attention with their growth in safety critical structures, more effort needs to go into selectively improving their electrical and thermal conductivities. Additionally, the ability to manufacture composite structures that can inherently monitor their own health will be exceedingly beneficial. This paper provides an overview of advances made towards multiscale composite manufacturing. Multiscale composites, especially with the use of carbon nanotubes, have been sought to provide enhanced structural (through-thickness) properties and increased electrical and thermal conductivities. This report will review the state of art in the manufacturing of multiscale composites, their scalability, and their inherent potential for multifunctionality. Current techniques mostly result in the application of carbon nanotubes throughout the entire laminates, rather than in selected areas. Subsequently, one of the main barriers, to the widespread use of carbon nanotube-applied composites, is an efficient mass-producible manufacturing process. This paper attempts to highlight the current knowledge gaps in this critical area of composites manufacturing.