On dynamics of origami-like structures: Necessity of enhanced models

Considering the dynamics of an origami-like rod, we demonstrate the need for improved discrete and/or continuum models of microstructured materials. Our origami rod consists of rigid or elastic links connected by torsion springs. The relatively simple one-dimensional model discussed here is an example of so-called torsion-dominant structures, where torsional (rotational) interactions play a crucial role. We have derived the exact form of the kinetic energy of the discrete structure. An extended continuum model is proposed. The dispersion properties of both the discrete and continuum models are analyzed. The main conclusion is that conventional (first-order) models are insufficient to capture the dynamics of origami-type and other deployable structures, where torsion and rotational effects are essential; therefore, generalized continuum models are necessary.