Functional, Durable, and Scalable Origami-Inspired Springs

Origami has recently emerged as a platform for building functional engineering systems with versatile characteristics that targeted niche applications. One widely utilized origami-based structure is known as the Kresling origami spring (KOS), which inspired, among many other things, the design of vibration isolators, fluidic muscles, and mechanical bit memory switches. Previous demonstrations of such concepts were carried out using paper-based KOSs, which are suitable for conceptual illustrations but not for implementation in a real environment. In addition to the very low durability resulting from the high plastic deformations at the paper folds; lack of repeatability, and high variation of performance among similar samples are also inevitable. To circumvent these issues, this paper presents a novel approach for the design of a non-paper based KOS, which mimics the qualitative behavior of the paper-based KOS without compromising on durability, repeatability, and functionality. In the new design, each fundamental triangle in the paper-based KOS is replaced by an inner central rigid core and an outer flexible rubber-like frame, which are fabricated out of different visco-elastic materials using advanced 3-D printing technologies. The quasi-static behavior of the fabricated springs was assessed under both compressive and tensile loads. It is shown that KOSs with linear, softening, hardening, mono- and bi-stable restoring force behavior can be fabricated using the proposed design by simple changes to the geometric design parameters, further pointing to the vast range of potential applications of such springs.