To drive snap-through in a bistable device or actuator, a non-mechanical stimulus (e.g. thermal, electrical, chemical...) is typically applied to the entire shell. This can mean high energy input and large amounts of active (i.e. stimulus-responsive) materials. Here, we show that you can make spherical caps snap with much less active material, without requiring a higher stimulus--as long as the active region lies on the shell boundary. This result is stimulus-agnostic, and can be mapped to many non-mechanical loads. We demonstrate with experiments using both swelling and magnetic stimuli.

L. Stein-Montalvo, J.H. Lee, Y. Yang, M. Landesberg, H.S. Park, and D.P. Holmes. Efficient snap-through of spherical caps by applying a localized curvature stimulus. European Physical Journal E, 45, 3 (2022) doi: 10.1140/epje/s10189-021-00156-0