Uncovering rotational multifunctionalities of coupled Kresling modular structures

Origami-inspired designs for structural and material systems have received significant attention due to their attractive kinematic and mechanical properties, design flexibility, reconfigurability, and multifunctionality. While promising, almost all studies have been focusing on the translational motion/deformation of structures and materials. Little attention has been given to origami-based designs in rotational elements, such as joints, shafts, and motors, despite the ubiquity of such functions in engineering. This research advances the state of the art through introducing a new coupled Kresling modular structure (CKMS) concept to achieve pure rotational motions created by integrating two Kresling origami tube modules with opposite chirality. A model with nondimensionalized parameters is first developed to investigate the various kinematic and mechanical properties of CKMS. Results show that several key CKMS rotational characteristics, such as multistability, energy absorption, and tunable stiffness can be programmed by varying key geometric design parameters. We find that interactions between modules may give rise to an asymmetric bistable property that enhances energy absorption. The CKMS enables tunable stiffness and quasi-zero stiffness (QZS) in rotation, which can be harnessed for vibration isolation. Furthermore, the proposed CKMS exhibits self-locking, a feature of certain origami patterns that arises from panel contact and offers a means to change stiffness significantly. Design guidelines to synthesize the multiple functionalities and mechanical properties explored in this research are discussed. The outcomes lay the foundation for origami-inspired structures that can transmit torque, isolate torsional vibrations, and absorb energies in rotational systems. (C) 2020 Elsevier Ltd. All rights reserved.