Collapsible Ball May Lead to'Foldable'Structures

摘要

In Civil engineering, buckling is typically associated with failure and is therefore avoided at all costs. But a group of engineers at the Massachusetts Institute of Technology (MIT) and Harvard University are making buckling an important design element in an effort to create the simplest three-dimensional struc-ture that can collapse reversibly. The result is a device they call the Buckliball. Inspired by a collapsible spherical toy with a complex ar- rangement of 26 moving elements and 48 rotating hinges, the Buckliball is a hollow sphere made of soft rubber. Unlike the toy that inspired it, the Buckliball contains no moving parts. Instead, it has 24 strategically placed dimples, a series of thin ligaments forming columns between the lateral dimples, and a series of thicker ligaments forming rows between the dimples. When air is sucked out of the Buckliball with a syringe, the thin ligaments collapse and the thicker ligaments undergo a sequence of movements described by the researchers as a cooperative buckling cascade, some rotating clockwise and others counterclockwise.