Architecture design of periodic truss-lattice cells for additive manufacturing

The development of additive manufacturing (AM) technology exhibits potential for the design and manufacturing of complex lattice structures. Herein, a novel design strategy is proposed for the lattice unit cell configurations, including triangular prism (T), quadrangular prism (Q) and hexagonal prism (H), by considering the tight spatial arrangement and manufacturing constraints. Moreover, the influence of altering the degree of freedom of nodes, caused by additional struts, on mechanical performance and energy absorption capacity is systematically investigated by theoretical modeling, experimental characterization and finite element method. A series of lattice core sandwich panels is designed and manufactured by selective laser melting (SLM). X-ray micro-computed tomography (μ-CT) is carried out to obtain the realistic geometrical information. Quasi-static uniaxial compressive tests are performed to investigate the failure mechanism and mechanical performance. The results reveal that the joint connectivity of the unit cell increased with the increase of the number of the struts, resulting in superior compressive modulus and ultimate strength. The main deformation mode of cells is gradually changed from bending-dominated to stretch-dominated with the increase of the joint connectivity. The proposed design ensures the performance consistency of the manufactured struts and facilitates the theoretical predictions and analysis. Furthermore, the specific energy absorption of the structure also increased with the increase of joint connectivity. In the case of unit cells with different configurations, T series rendered superior specific strength and specific energy absorption, whereas Q series exhibited excellent specific stiffness.