Modeling self-folding of large-scale structures

We study the morphing of large-scale origami-inspired active structures made from strong and lightweight biodegradable polymer composites. Such morphable structures in response to external stimuli could form the basis for sustainable architecture and be an alternative to traditional construction processes with reduced cost, waste, and energy consumption. Though the basic design principles of small-scale self-morphing origami are well understood, it is unclear how these designs need to be adapted when gravitational loads become relevant. To investigate the role of gravity and material/structural properties, we created a two-part computational model to guide the design of self-morphing large-scale origami structures. The first part, based on finite-strain theory, models individual origami folds that curve because of differential swelling/contraction across the multi-layered material. This analysis helps identify parameter regimes that lead to foldability of the activated hinges in the presence of gravity. These results form the basis for the second part which is a coarse-grained discrete bar-hinge model with active torsion and elastic springs, and vertex loads. Both parts work together to relate local material/structural properties of activated folds to the global structure deployed on the ground.