Tuning the Properties of Multi‐Stable Structures Post‐Fabrication Via the Two‐Way Shape Memory Polymer Effect

Multi‐stable elements are commonly employed to design reconfigurable and adaptive structures, because they enable large and reversible shape changes in response to changing loads, while simultaneously allowing self‐locking capabilities. However, existing multi‐stable structures have properties that depend on their initial design and cannot be tailored post‐fabrication. Here, a novel design approach is presented that combines multi‐stable structures with two‐way shape memory polymers. By leveraging both the one‐way and two‐way shape memory effect under bi‐axial strain conditions, the structures can re‐program their 3D shape, bear loads, and self‐actuate. Results demonstrate that the structures' shape and stiffness can be tuned post‐fabrication at the user's need and the multi‐stability can be suppressed or activated on command. The control of multi‐stability prevents undesired snapping of the structures and enables higher load‐bearing capability, compared to conventional multi‐stable systems. The proposed approach offers the possibility to augment the functionality of existing multi‐stable concepts, showing potential for the realization of highly adaptable mechanical structures that can reversibly switch between being mono and multi‐stable and that can undergo shape changes in response to a change in temperature. Cutting‐edge assemblies of multi‐stable structures with two‐way shape memory polymers allow on‐demand transformations of shape and stiffness of the structures. The structures' shape can be re‐programmed to bear loads or suppress multi‐stability. Results show potential for the realization of adaptable mechanical systems that reversibly switch between mono and multi‐stable and self‐actuate in response to temperature changes.