Flex-actuated bistable dome: a simple low-profile structure for sensing, controlling, and utilizing flexural forces.

A flex-actuated bistable dome is a shallow indentation in thin strong material formed so that when the material around a dome is bent toward the same side as the dome it will buckle and snap toward the outside of the curvature. This simple one-piece mechanical structure can be made in a wide range of scale. Bistable domes with overlapping perimeters are structurally connected and share the flexural forces that switch individual domes. They can neutralize flexural forces by switching sides in numbers proportional to curvature.

Tactile digital bend and shape sensor: Overlapping flex-actuated bistable domes can be used in a paper-thin flexible circuitry laminate to make bend and shape sensors that automatically digitize flexural forces caused by bending. The digital patterns relate to where, how much, and which direction from flat the sensor is bent. A very thin sensor that knows it's own shape can be created. Products range from simple flex-sensitive compound switches and digital bend sensors to multidimensional shape sensing and object recognition. Can be used for monitoring curvature, displacement, impact, force, motion, pressure, timing, position, weight, fluid motion.

......NEW.... See more shape sensor prototype photos.
See :
single row shape sensor prototype videos demonstrating 2D profile and bend digitizing capabilities.
See: shape sensor design example for flexible circuitry.

US Patent # 5563458. Apparatus and Method For Sensing Surface Flexure. (Use contact address below).

Controlling springback and creating shape memory in thin high strength materials. Arrays of closely packed shallow overlapping bistable domes constructed in thin high strength sheet metal form a stiffer structure several times the original thickness that can be bent and rebent with little or no springback. Wherever it is bent the local bistable domes adjust their orientations incrementally to neutralize flexural forces and hold the new shape. Similar bistable domes can be used to create flexural forces in high strength sheet metal while in a flat plane so that it has a predisposition to assume a desired shape as soon as it is freed to do so. This new technology may help in prototyping and reduce stamping and tooling requirements. It also presents opportunities for stronger and lighter construction that may improve fuel efficiency for the transportation industry, for example.
See text of Metalforming Magazine article.
See also "Bi-stable Concepts for Reconfigurable Structures", K.A. Seffen, Dept. of Eng., University of Cambridge, UK.

Bistable dome array:

See more array images (192k).

Bistable dome pump- a flexible pump that pumps when bent: A very simple pump that can utilize a wide range of natural or mechanical motion. Small or large scale wind and wave power renewable energy applications. Water and pressure supply, desalination, mariculture/aquaculture, reoxygenation, oil spill management, medical, lubrication, etc. Low cost appropriate technology applications. US Patent # 6132187. Flex-actuated Bistable Dome Pump. (Use contact address below).

Paul Ericson
email: barkingpo at

PO Box 576
Cerrillos, NM 87010

And for something completely different: seed dispersal by fish.