A novel hybrid lattice structure for improving compression mechanical properties

Lattice structures are widely used in load-bearing and energy-absorption applications for their lightweight, high specific stiffness, high specific strength and excellent energy-absorption. A novel hybrid lattice cell that combining octet cell and body-centered cube cell was proposed, and quasi-static compression experiments and finite element simulations were performed to investigate their energy-absorption characteristic and deformation mechanisms. The effects of the relative density, configuration of cell and component ratio sub-cell on the compression responses were also explored. The results showed that hybrid lattice improves compression modulus and yield strength by 10% and 16% maximally, respectively, and the energy-absorption of enhancement is 20% higher than the conventional lattices. In addition, the hybrid lattice can significantly alleviate the stress softening. By increasing the volume ratio of body centered cubic in the hybrid lattice structures, the energy-absorption can be improved. Under dynamic loading, the proposed hybrid lattice structures displayed outstanding normalized yield strength, which is superior to majority of porous structures. Inspired by the precipitation hardening mechanisms used in metallurgy to design high-performance alloys, two dual-phase lattices are developed. The quasi-static compression of dual-phase lattices shows three stages plateau stress and has a higher third stage than that of traditional dual-phase lattices. These findings provided design strategy for lightweight structure.