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

TL;DR

This paper introduces a simple, single-material 4D printing method that uses spatially patterned strain trapping to create programmable, shape-morphing structures with one-way actuation, accessible via desktop FDM 3D printers.

Contribution

It develops a novel shape-memory strain programming technique called Programming via Printing (PvP) that eliminates secondary post-processing and enables complex deformation modes.

Findings

Achieved up to 50% controlled trapped tensile strain.

Validated deformation modes at unit-cell level and in larger structures.

Demonstrated scalability and practical application of the method.

Abstract

A single-step, single-material 4D printing method is developed for programmable structures featuring spatially patterned strain trapping for one-way actuation. This approach enables fabrication on desktop fused filament fabrication 3D printers through a recently developed shape-memory strain programming method, Programming via Printing (PvP), which eliminates the need for secondary post-fabrication programming. Large (up to 50%) and spatially controlled trapped tensile strain programming is achieved by PvP model design, geometric coding, and printing parameter optimization. While contraction naturally arises from printing-induced trapped strain, expansion is introduced via architected lattice designs with patterned strain-enabling a full range of deformation modes. These capabilities, validated at the unit-cell level, are further integrated into larger proof-of-concept structures to demonstrate scalability and practical implementation. This strategy provides an accessible, low-cost, and easily adoptable additive manufacturing approach for diverse functional-material applications.