Deployable fiber-reinforced polymer for advanced monolithic Rigid–Soft robotics applications

Deployable structures, particularly those inspired by origami, have garnered significant attention for their compact storage and efficient deployment capabilities. This study proposes a multi-resin dispensing process for fabricating monolithic fiber-reinforced polymer (FRP) structures tailored for rigid–soft robotics applications. Combining rigid and flexible epoxy resins enables precise resin patterning, overcoming the limitations of traditional single-resin systems. This approach allows the selective imparting of mechanical properties within monolithic structures, facilitating deployment mechanisms and ensuring stability under repetitive cycles without hysteresis. The resulting FRP structures exhibit a flexural modulus of 6.95 GPa for rigid sections and 0.66 GPa for foldable sections, allowing selective folding with a radius of curvature less than 0.5 mm. The successful fabrication of a monolithic composite with a triangulated cylindrical origami (TCO) structure highlights the potential for mass production of advanced FRP structures, suitable for next-generation rigid–soft robotics and aerospace applications. Unlike existing soft materials, the TCO FRP demonstrates durability under repeated deployments at high strains of up to 80 %, producing a significant deployment force of 2.75 kgf, enabling repetitive motion. This advancement broadens the scope of composite materials, facilitating adaptable, scalable solutions with selective rigidity and flexibility.