Experimentally-validated computational modeling and characterization of the quasi-static behavior of functional 3D-printed origami-inspired springs

The presence of Origami patterns in the anatomy of many biological species compels a thorough understanding of their underlying mechanics and possible utilization in man-made systems. Along this line, the past decade has witnessed an increased interest in Origami inspired engineering, where it was shown that foldable and spatially-expandable structures with rich kinematics and unconventional Poisson's ratio can be created using different Origami patterns. Among those, the Kresling Origami pattern has inspired the design of springs with nonconventional properties. Here, we develop a representative shell-based finite element model for predicting the quasi-static mechanical behavior of a class of 3D printed Kresling Origami springs. We validate the model against experimental data, then use it to generate maps that demarcate regions in the design parameter space into qualitatively different behaviors of the springs. We show that, depending on their design parameters, the springs can exhibit a linear elastic behavior; a nonlinear elastic softening/hardening mono-stable behavior; quasi-zero stiffness behavior; or even a bi-stable behavior. The modularity of these springs, their tunability, and the ability to combine them permits architecturing metamaterials with tunable constitutive laws, which could potentially revolutionize the design of shock absorbers and cushion materials.