Shape adaptive multi-stable composite grids
Multi-stable structures have multiple geometries that correspond to minima of the strain energy and can therefore be held passively. The periodic extension of bi-stable composite unit cells is a common approach to the realization structures with hundreds of stable states. In practice however, this is severely limited due to interaction of boundary conditions between neighboring unit cells. Instead, we investigate the shaping of composite grids using soft pre-stretched elastic membranes. The resulting surfaces show high-displacement shape-adaption, are insensitive to boundary condition interactions between cells, and exhibit enhanced multi-stability in the periodic structures as compared to the unit cell. We are particularly interested in exploring the following aspects of these structures:
- The effect of the composite material anisotropy on the multi-stability of the structures
- Integration of lightweight actuation into the structures and reduction of actuation effort in large structures
- Efficient modelling of highly multi-stable structures
The resulting shape adaptation has been leverage for locomotion in soft robots.
Collaborators:
Dr. P. Ermanni and G. Risso at CMASLab, ETH Zurich
Related Publications:
- Risso, G., Sakovsky, M., & Ermanni, P. (2022). A Highly Multi-Stable Meta-Structure via Anisotropy for Large and Reversible Shape Transformation. Advanced Science, 2202740.
- Risso, G., Rogenmoser, T., Sakovsky, M., & Ermanni, P. (2022). Programmable FRP metamaterials for adaptive hinges with multiple 3D shapes. 2022 AIAA Scitech Forum.
- Risso, G., Sakovsky, M., & Ermanni, P. (2021). Highly multi-stable pre-stretched FRP grids for shape adaptation. AIAA Scitech Forum 2021.
- Risso, G., Sakovsky, M., & Ermanni, P. (2021). Instability-driven shape forming of fiber reinforced polymer frames. Composite Structures, 268, 113946.
Funding:
Swiss National Science Foundation (#200021_192082)