Integrated electrical connections in deployable composite tube flexures

Abstract This study extends the functionality of ultra-thin carbon fibre composite tube flexures by interleaving a multi-layered conductive film along the laminate’s midline to enable data and power transmission across the structural joint. Conductive tracks, created by silver nanoparticle deposition onto a polyimide substrate, are encapsulated by a thermoplastic film to prevent short-circuits with the carbon fibres. The paper first establishes the mechanical stability of the integrated structure through analysis and testing, then investigates the electrical signal integrity and the feasibility of thermal actuation for a shape-memory use-case. Repeated moment-rotation tests showed a progressive reduction in locking moment. The conductive track remained functional, without showing an appreciable degradation in signal quality or electrical resistance. Resistive heating tests reaching higher temperatures caused adhesive failure between the thermoplastic film and the tracks in the stowed state, leading to local delamination and catastrophic failure of the laminate. These findings demonstrate that novel inkjet-printed conductive interleaves are a viable solution for digital signal and low-power transfers in laboratory conditions, raising the challenge of extending testing to space-like environments and improving the bond strength of the silver tracks for enhanced thermal durability. This methodology represents a significant step forward in terms of structural power integration, enabling ultra-lightweight harnesses to be directly integrated within highly strained deployable members with applications on small and large satellites, as well as next generation space structures, such as space-based solar power stations.