The structure was printed by direct ink writing (DIW) method to deposit a polyurethane elastomer material with water-swelling characteristics on a heat-shrinkage shape memory polymer material to form a bilayer structure. proposed a 4D printing strategy with a dual stimuli-responsive shape-shifting structure that responds to both temperature and water. The existing 4D printing technology is mostly subjected to only responsiveness to a single stimulus. The printed structure has multi-stable features and the stiffness of the deformable structure is dramatically reduced under thermal triggering. fabricated a typical hexagon-twist origami structure via multi-material printing technology. Multi-material printing processes that can respond to diverse stimuli have become a research hotspot in 4D printing. Through experiments and finite element analysis, it was demonstrated that the pre-strain plays a key role in the deformation and also greatly accelerates the actuation of the bilayer structure. A bilayer structure with one pre-strained layer and the other non-pre-strained layer was integrally printed. proposed a pre-strained strategy to accelerate the actuation of thermal responsive structures. The two components were programmed to have the deformation behavior and stimulated by thermal expansion mismatch between polylactic acid (PLA) and carbon-fiber-reinforced PLA. presented a structure design using alternate actuation to attain competent loading capacity in different deformed states. The lattice was built based on a hexagonal honeycomb structure, demonstrating tunable shape reconfigurability as the ambient temperature changes, which was investigated by experiment and simulation. developed a shape reconfigurable, highly stretchable lattice structure with tunable Poisson’s ratio. As a result, the structure design is of particular importance. The printed component showed excellent repair effect with a tensile strength of 50.93 MPa and a recovery rate of up to 87.22%.īesides the intelligent materials, another representative way to realize 4D printing is through non-intelligent materials combined with specific structure design. The material was prepared by melamine-formaldehyde resin microcapsules using in-situ polymerization, and then it was fabricated through a 3D printer.
prepared a kind of self-healing material that is a promising intelligent material. The intelligent hydrogel actuator reached an effective displacement of 20 mm within 10 s through the forward movement, providing a material candidate for practical applications of 4D printing in the soft robot, information sensing, and health engineering. fabricated a near-infrared laser driven intelligent hydrogel actuator system via extrusion-typed 3D printing and hydrothermal synthesis. Therefore, many researchers are interested in developing new intelligent materials. The most popular way to develop 4D printing is to adopt intelligent materials in the AM process. It is encouraging that this Special Issue on 4D printing has collected ten articles, covering research on the materials, structures, functionalities, and applications in 4D printing. Therefore, 4D printing is a very promising and valuable research field. The 4D printed products have vast potential for various applications in the field of aerospace, automotive, biomedical, and soft robots, etc. The main challenges that need to be addressed are the implementation of the change in properties and functionalities, as well as research on simulation technology for 4D printing. In recent years, a growing body of research has investigated the change in shapes of the 4D printed components. 4D printing, a cutting-edge branch of additive manufacturing (AM) technology, shows the capability of fabricating intelligent components through the active design of smart materials and structures, as well as the shapes, properties, or functionalities that can controllably vary with time and space dimensions.
It is a revolutionary manufacturing technology based on the high degree of cross-integration of the disciplines including materials, mechanical engineering, dynamics, and informatics, etc.
Four-dimensional (4D) printing has received widespread attention since its conceptualization in 2013.
0 kommentar(er)
