Hebrew University Team Finds New Geometric Rule for Self-Shaping Materials

Hebrew University researchers identified a previously unrecognized topological constraint that forces growing elastic sheets to stop expanding smoothly and form periodic cone-shaped dimples. Yafei Zhang, Michael Moshe and Eran Sharon combined mathematical analysis, computer simulations and elastic-shell experiments, finding that the transition occurs after accumulated positive curvature reaches a geometric horizon. A single cut removed the obstruction, showing that the effect depends on the sheet's overall connectivity rather than defects or local geometry. The team says the principle could inform self-shaping materials for soft robotics, medical devices and space technology.