Design, fabrication and mechanical properties of a new cylindrical lattice metamaterial

In this paper, a novel rotating sweep method was introduced for the design of lattice metamaterials. Using this method, we first designed a metal-lattice cylinder metamaterial with simple truss unit cell (Rhombic_cylinder) and prepared this metamaterial by the unsupported metal laser powder bed fusion (LPBF) technique. After the preparation of the specimen, microscopy test was used to examine the quality of the specimens and to verify the reliability of the manufacturing technique. Then, the mechanical properties of the Rhombic_cylinder metamaterial were studied through experimental and simulation methods, compared with those of the traditional 2D truss lattice (Truss_2D) metamaterial. The results show that the specific energy absorption and the equivalent elastic modulus of the Rhombic_cylinder are increased by 186 % and 600 %, respectively, compared with the traditional Truss_2D. In addition, the proposed structure was compared with the existing 2D and 3D lattice structures in the literature, showing exceptional advantages in the mechanical performance. Finally, we extended the rotating sweep method to the design of other 3D lattice structures, such as the hexagonal cylindrical lattice metamaterial, and studied their mechanical properties using the verified finite element (FE) numerical model. The results verified that the proposed rotating sweep method is applicable to different 2D lattice cell geometries to achieve improved mechanical properties. This design and fabrication approach provide a new paradigm for the development of metal lattice metamaterials, to be potentially applied to civil engineering, aerospace, vehicle collision avoidance and other fields.