Morphing with diamonds*

Morphing flat structures into 3D surfaces generally involves metric change as dictated by Gauss’ theorem. We exploit the deformation of diamond tilings to transform initially flat objects into 3D structures. Such diamond cells deform biaxially when activated. The local strain anisotropy is controlled by the orientation and the initial angles of the diamond cells. As a result, different shapes can be programmed ranging from negative to positive Gaussian curvature. We discuss two applications of this general principle. A diamond mesh cut from a thin sheet of mylar embedded in an expanding matrix constrains its deformations and sets the 3D shape of the deployed structure. Conversely, the entire object can be a thicker 3D-printed network of diamond cells. The amount of closing of the cells controls the effective local deformation of the structure and can be tuned by adding blockers inside the cells. Actuation of the cells is achieved by tension wires or vacuum. We will discuss the shapes and mechanical properties of these activated structures.