Compliant morphing structures from twisted bulk metallic glass ribbons

The study explores how to make fully metallic structures that can change shape. It starts with initially flat metallic glass ribbons, twists them into a helicoidal geometry, and then thermoforms them so that this helicoidal shape becomes the stress-free reference state. Because the helicoidal geometry varies the ribbon’s preferred bending direction along its length, the ribbons behave like compliant joints. This allows multiple deployed and stowed configurations that the authors say would be unachievable without the pre-twist, assuming compaction does not cause material failure. The work also combines numerical simulations with an analytical shell-theory model and torsional experiments to study how different ribbon geometries respond to finite twisting. The authors report that ribbons with undulated edges can localize twisting deformations onto desired regions before thermoforming, and they demonstrate that multiple ribbons can be joined to form deployable systems.