An overview of the mechanical description of origami-inspired systems and structures

Origami is inspiring several fields of knowledge such as engineering, aerospace systems, medicine, and biomechanics, motivating the creation of novel adaptive and morphing systems and structures where smart materials are employed for actuation. The combination of low energy processes and inherent foldability allows the design of optimized systems widely applicable, ranging from nanoscale to megascale. This article deals with a general overview of the mechanical description of origami-inspired systems and structures, discussing their fundamentals, applications and modeling approaches. A critical review of the mechanical modeling is discussed considering either kinematic-based or mechanic-based formulations. A collection of results is reported to allow a comparison of the best strategies to deal with the complex behavior of origami systems and structures. Kinematic-based formulations are presented with a special interest on developing reduced-order models. Equivalent mechanisms and direct geometric approaches are treated exploring symmetry hypotheses as the basis to build proper reduced-order models. Mechanic-based formulations are treated as a reference description using finite element analysis. The comparison of the different descriptions allows one to establish reduced-order model range of validity, which is a powerful tool for design purposes. Nonlinear dynamics of origami systems and structures are reviewed exploiting the use of reduced-order models. A rich and complex behavior originated from the combination of geometrical and constitutive nonlinearities is stated.