Design and realization of multiunit functional primitives based on 4D printing

By leveraging the synergy between 3D printing and smart memory materials, this approach allows structures to adapt their shapes, performance, and functions in response to external stimuli. This study primarily investigates the precise control of deformation in single-material structures, offering simplicity and rapid manufacturability compared with multi-material approaches. This study establishes a correlation between the manufacturing parameters and deformation curvature in bilayer actuators using fused deposition modeling (FDM)-4D printing. It further explores how the area ratio of different units within the design plane influences the deformation of the folding functional primitives. An optimization process using the NSGA-II algorithm fine-tunes both the area ratio and manufacturing parameters, achieving a Pareto front that optimizes the deformation of these primitives. Experimental validations confirmed the effectiveness of this method, demonstrating control over the primary deformation within the prescribed parameters while ensuring structural deformation quality. This method was applied to complex structures, such as triangular pyramids and hexahedral shapes, illustrating its practicality. This paper concludes by acknowledging the limitations of this method and proposing future enhancements through machine learning and improved FDM structural models. These advancements are aimed at enhancing the reliability of 4D printed structures, paving the way for their application in transformable vehicles and other advanced fields.