Design space of embeddable variable stiffness bi-stable elements for morphing applications

The challenge of accomplishing efficient morphing entails providing a vastly anisotropic internal architecture. As a possible solution, selective compliance can be imparted on a larger structural system by embedding its interior with elements exhibiting variable stiffness properties. Multi-stable laminates, which feature markedly different characteristics corresponding to each equilibrium configuration, become promising variable stiffness components. This paper explores the design space of two classes of bi-stable composites specially designed to provide stiffness variability in distributed compliance systems. A further requirement of embeddability is imposed, denoting the ability to constrain two opposite edges of the element without bi-stability loss. Given these two central aspects, the spatial distribution of the piece-wise lamination regions and the overall aspect ratio of the configurations are varied using experimentally validated finite element analysis. Hence characteristic trends are identified, expected to greatly facilitate the design process of shape-adaptable selectively compliant systems based on integrated bi-stable components for stiffness variability.