Our latest work in collaboration with Tom Vogel, Aghna Mukherjee, Edouard Tarter, and Paolo Ermanni from ETH Zurich investigates how to improve stiffness in bi-stable mechanisms. Designing bi-stable structures to have sufficient stiffness to carry operational loads while simultaneously being sufficiently compliant to achieve large shape morphing is a persistent challenge in adaptive structures. We propose kinematics-driven criteria to design assemblies of bistable elements. Compliance is achieved at the material level by utilizing thin fiber reinforced composite materials to limit the stresses in the material during deformation. We reveal the best structural architectures to improve stiffness of the overall mechanism through geometry.
The potential of the approach is demonstrated on a reconfigurable inspection arm. Three bi-stable units re-orient a camera along two rotational axes while meeting real-world stiffness requirements for a spacecraft mission. Actuation using shape memory alloy springs allows reversible reconfiguration.
See the full article published in Materials & Design at https://doi.org/10.1016/j.matdes.2024.113154
