Deployment Dynamics of Origami Sheets and Fluidic Origami Tubular Structures

Abstract

In recent research investigations, Origami has shown great potential for creating reconfigurable structures for achieving various engineering functions. Especially, origami can be designed to fold compactly into very small volumes and then deploy to become large structures, which has led to many deployable system applications. Despite their promising potentials, most origami studies have focused on their static or kinematic features, while the complex and yet important dynamic behaviors of the origami deployment process have remained largely unexplored and unknown. To discover the missing knowledge, this thesis research investigates the dynamics of origami structure deployments, with a focus on Miura origami sheets, fluidic origami tubes, and fluidic multi-tube origami structures as testbeds. We construct a dynamic model for origami structures that captures the combined panel inertial and flexibility effects, which are otherwise ignored in rigid folding kinematic models but are critical in describing the dynamics of origami deployment. Our non-dimensionalized models provide rich new insights on how the deployment dynamic response is influenced by structural properties and other input parameters. This research advances the state of the art with new findings that have not and many times cannot be derived with traditional analyses.

Results from studying the Miura origami sheet show that the structure’s deployment path may substantially deviate from a nominal quasi-static unfolding path based on the rigid folding assumptions, especially when the panels are more flexible. Additionally, it is shown that the pattern geometry influences the effective system stiffness, and therefore subtle changes in the geometric parameters can result in qualitatively very different dynamic behaviors, where the Miura origami sheet may snap into different stable equilibria during the deployment process.

In the investigation of the fluidic origami tube, the ends of the tube are sealed and a space-invariant fluidic pressure field is first applied internally as a step function. The dynamic deployment results reveal that the internal pressure level can influence the structure’s transient response and the final tube configuration. Additionally, results indicate that adjusting the fluidic pressure varies the effective stiffness and damping ratio of the system, and thus affects the tube’s transient dynamic response during deployment. The multistability landscape of the fluidic tubular origami further enriches the deployment dynamics. By applying the fluidic pressure as a ramp function in time, we show that by controlling the pressurization rate, the tube can possess different transient behaviors and can settle at different stable configurations.

For the fluidic multi-tube origami structure testbed, we build models with different designs of the interface between tube elements. Results show that the multi-tube structure could have more complex behaviors than the single tube structure. The pressurization method and boundary conditions can influence the deployment significantly, where the structure can achieve a different deployment extent and arch in different directions. Furthermore, it is shown that with depending on the interface designs, multi-tube structures can reconfigure among different stable equilibria under dynamic deployment.