Compressive behavior of functional graded hybrid lattice structure

Abstract Today, lattice structures are preferred in various fields, including biomedical, aviation, and the defense industry, due to their exceptional mechanical properties, low density, high specific strength, high specific stiffness, good energy absorption ability, and excellent thermal and acoustic insulation. This study focused on investigating the mechanical performance of functionally graded hybrid (FGH) lattice structures. Three types of lattice structures were designed: triple periodic minimal surface (TPMS)-based primitive-gyroid (P-G); body-centered cubic-gyroid (BCC-G); and primitive-body centered cubic (P-BCC) hybrid lattice structures. In addition, each hybrid lattice structure was formed both in the large porosity size and in the production direction from the large pore size to the small pore size. These hybrid lattice structures were then fabricated using selective laser melting (SLM). In the results of compression tests on FGH lattice structures with large pore sizes, the P-BCC structure exhibited the highest elastic modulus among the test specimens, measuring 1573.17 MPa. The highest yield strength was found to be 128.46 MPa in the BCC-G hybrid lattice structure. Furthermore, when evaluating the energy absorption capabilities of hybrid lattice structures with a large pore size, the BCC-G structure demonstrated the highest resilience and toughness among the test samples. On the other hand, an increase in elastic modulus, yield strength, and energy absorption values was observed with the decrease in pore size. However, it was observed that the change in pore size due to defects in the production of lattice structures is another effective parameter on mechanical properties. This study suggests that desired mechanical properties can be achieved through the functional grading of pore size and the creation of hybrid structures utilizing different lattice designs.