Self-Folding Laminated Composites for Smart Origami Structures

Origami-folding principles can be used with laminated composites to produce lightweight structures that are capable of drastic changes in shape. This paper presents a smart composite that can actively change its crease pattern to fold itself into different rigid shapes and provide a large range of motion. The composite uses a smart material with variable modulus sandwiched between two fiber-reinforced elastomeric skins, one of which is prestressed. Change in modulus of the sandwiched core layer allows prestress in the elastomeric skin to actuate the fold. Unfolding the structure to a flat shape can be accomplished through either embedded or external actuation. Passive composite panels were fabricated for model development and validation. An analytical model was developed based on classical laminate plate theory to study the influence of core modulus, core thickness, and elastomeric skin prestress on the equilibrium curvature of the composite structure. Selected smart materials that provide a change in modulus when stimulated are discussed as candidates for the core layer of the self-folding composite.