Mechanical behavior analyses of 4D printed metamaterials structures with excellent energy absorption ability

Mechanical metamaterials with immense specific energy absorption and high specific strength are extensively being applied in engineering fields, including bone tissue scaffolds, aerospace and automotive engineering. Many structural design strategies have been developed to improve their mechanical properties. The lattice metamaterials with a tremendous specific energy absorption capacity exhibit continual platform stress after initial yield and before densification. Here, combined with bionic design, we designed and fabricated a series of mechanical metamaterial with tension-dominated mechanical behavior which can assimilate enormous amounts of energy while maintaining a low density. The design strategy relied on the network construction in the periodic grid topology, which took the microstructure with several beams as the building block connecting the grid nodes. The mechanical properties can be adjusted by changing topology parameters. Additionally, the metamaterials fabricated by 4D printing technology show intelligent properties, which can jump from one mode to another under external stimulation. It was worth mentioning that the shape memory effect (SME) also endowed the material with certain self-healing properties. Excellent compressive resistance, energy absorption, shock absorption and shape memory effect suggest the application prospect in engineering fields.