That a domed shell structure can be inverted has been common knowledge for a long time, with children's toys employing the phenomenon. It has also been known that it is possible to increase the bending stiffness of thin sheets of metal by profiling them. It is possible to combine the two phenomena by profiling high strength metal sheets with spherical dimples. These sheets have the advantage of having both increased bending stiffness and a multitude of different stable configurations.
The research in this area has been focused on tailoring the bending stiffness of a strip of overlapping dimples with varying depth of profiling and overlap. For these tests, the strip was modelled in ABAQUS. The dimples were induced by applying compressive prestress in the strip at the location of the dimples. These areas of prestress deform out of plane to form dimples.
A large number of analyses were completed and the stiffness of each of the strips were plotted against the prestress and overlap.
![[Univ of Cambridge]](http://www.eng.cam.ac.uk/images/house_style/uniban-s.gif)
![[Dept of Engineering]](http://www.eng.cam.ac.uk/images/house_style/engban-s.gif)
![[Deployable Structures Laboratory]](http://www2.eng.cam.ac.uk/~ek235/dsl_logo.gif){kind=logo}