Poking of sheets and shells: how wrinkling reveals new isometries

Poking is a natural way to measure the world around us - how an object resists poking tells us how stiff it is. I will focus on the mechanics of this poking for objects that are extremely thin. Such objects are very difficult to stretch rather than bend and so their isometries (distance-preserving deformations) are natural ways of understanding their deformation. I will show that the thinness of these objects often leads to wrinkling and, in turn, to isometries that were previously unknown. contact: pasquale.ciarletta@polimi.it