Single-material 4D-printed shape-morphing structures via spatially patterned strain trapping

The work presents a single-material 4D printing method that creates programmable, shape-morphing structures by trapping strain in specific spatial patterns. The goal is one-way actuation, where the material deforms in a controlled direction. The method is implemented using desktop fused filament fabrication 3D printers and relies on a shape-memory strain programming approach called Programming via Printing (PvP). PvP is designed to achieve large trapped tensile strain (up to 50%) and to control where that strain is trapped by combining model design, geometric coding, and printing parameter optimization. The abstract also explains how contraction arises naturally from printing-induced trapped strain, while expansion is enabled through architected lattice designs that provide patterned strain-enabling deformation modes. Results are validated at the unit-cell level and then assembled into larger proof-of-concept structures to show scalability and practical implementation.