Programmable stiffness and shape modulation in origami materials: Emergence of a distant actuation feature

This paper develops an origami based mechanical metamaterial with programmable deformation-dependent stiffness and shape modulation, leading to the realization of a distant actuation feature.Through computational and experimental analyses, we have uncovered that a waterbomb based tubularmetamaterial can undergo mixed mode of deformations involving both rigid origami motion and struc-tural deformation. Besides the capability of achieving a near-zero stiffness, a contact phase is identifiedthat initiates a substantial increase in the stiffness with programmable features during deformation ofthe metamaterial. Initiation of the contact phase as a function of the applied global load can be designedbased on the microstructural geometry of the waterbomb bases and their assembly. The tubular metama-terial can exhibit a unique deformation dependent spatially varying mixed mode Poisson’s ratio, whichis achievable from a uniform initial configuration of the metamaterial. The spatial profile of the meta-material can be modulated as a function of the applied far-field global force, and the configuration andassembly of the waterbomb bases. This creates a new possibility of developing a distant actuation fea-ture in the metamaterial enabling us to achieve controlled local actuation through the application of asingle far-field force. The distant actuation feature eliminates the need of installing embedded complexnetwork of sensors, actuators and controllers in the material. The fundamental programmable featuresof the origami metamaterial unravelled in this paper can find wide range of applications in soft robotics,aerospace, biomedical devices and various other advanced physical systems.