Session: SYMP 4-7: Multi-stable Smart Systems

Paper Number: 141765

141765 - Multistable Morphing Surface for Interactive Reconfiguration 

Morphing structures have attracted significant interest due to their ability to reconfigure their geometry to maintain optimality over a wide range of operational conditions. Conventionally, morphing is achieved by combining a shape-morphing structure augmented by sensors and actuators. The combination of several systems inevitably imposes competing restrictions that can lead to added complexity and suboptimal performance. Compliant-based morphing structures with inherent reconfiguration capabilities can provide a route to address these limitations. One class of such morphing systems are multistable structures that exhibit several stable shapes by design, for example, leveraging prestress or geometrical incompatibilities. In contrast to conventional compliance-based morphing structures, the inherent shape reconfiguration between stable states in multistable structures does not require either constant work application to hold deflected shapes or closed-loop control to ensure a desired geometry. These advantages come at the cost of forgoing access to a continuous configuration space for a discrete one formed by the designed stable shapes of the structure. Additionally, most multistable structures exhibit geometrically simple shapes as per their (nearly) zero Gaussian curvature (cylindrical shapes), implying most curvature variation aligns in a single coordinate direction. The limited number of stable shapes of most multistable structures, typically two, and simple geometrical complexity constitute significant roadblocks impeding their widespread application.

Recently, multistable metastructures based on dome-patterned sheets with locally bistable units have been demonstrated to exhibit a broad range of possible shapes. Importantly, this class of multistable metastructures can display many more than two stable states with complex geometries, i.e., with doubly curved and saddle-shaped geometries (i.e., non-Zero Gaussian curvature), as well as the conventional cylindrical shapes.

We present a morphing surface demonstrator based on dome-patterned sheets that exhibit several geometrically complex shapes accessible via open-loop control inputs. This class of structures allows for programming multiple desired shapes based on the unit cell and pattern of the design. Specifically, we employ a metastructural design composed of two dome-shaped sheets arranged to generate an inflatable chamber. The chamber design allows for retaining the complex reconfiguration of dome-patterned sheets while providing a simple mechanism for actuation via inflation. Notably, the actuation input is only needed to access the desired shapes, thus reducing the actuation complexity. Furthermore, additional reconfiguration can be achieved by external force inputs, allowing users to change the structure’s shape interactively. The geometrical complexity, rich configuration space, and simple actuation of the presented multistable metastructures provide a promising blueprint for the design of functional morphing structures.

Presenting Author: Jhonatan Rincon Purdue University

Presenting Author Biography: Jhonatan earned his BS in Mechanical Engineering from Universidad Nacional de Colombia in 2023. Currently serving as a Visiting Scholar at Purdue University, his research focuses on compliant morphing structures, additive manufacturing, and the application of origami theory to deployable and reconfigurable structures.

Authors:

Jhonatan Rincon
Gunes Kosterit
Juan C. Osorio
Paul A. Loughlin
Wonhee Kim
Paul Alexander
Andres F. Arrieta