This project extends the concept of the 1D bistable arch unit to a 2D structure, resulting in a frame unit that exhibits a characteristic "dimple" shape. The unit's stability and deformation modes can be tuned by connecting the base with arches in various configurations: plus, cross, or spider. (See the preceding 1D Bistable Arch project).

To understand the mechanical behavior and snapping forces of a single unit, we performed mechanical testing and 3D scanning.

A 3x3 array of the cross-unit exhibits mechanical memory. This means the array can transition to different cylindrical shapes based purely on the sequence and order in which the individual units are actuated, as demonstrated in the inset.

Here is a timelapse illustrating the snapping process for the first actuation sequence.

The preprint version of this paper is hosted on engrXiv.