4D Printing Pre-Strained Structures for Fast Thermal Actuation

Four-dimensional (4D) printing is an emerging technology by adding the dimension of time-dependent reconfiguration into 3D printing. It enables printed structure to change shape, property, or functionality under external stimuli such as temperature, magnetic field, and light, etc. Among existing 4D structures, thermal responsive structures are widely used for their easy operation. However, slow actuation impedes applications like soft robotics. In current work, a pre-strained strategy proposed accelerate structures. A platform that can apply strain during process constructed fabricate aid in-situ tensile base. bilayer with one layer other non-pre-strained integrally printed. Through experiments finite element analysis, it demonstrated aspect ratio has little effect on deformation structure, whereas pre-strain plays key role in also greatly accelerates structure. Based energy-free gripper fabricated fully crawler achieve high running speed.