Uniform and graded bio-inspired gyroid lattice: Effects of post-curing and print orientation on mechanical property

Abstract

Additive manufacturing is spreading rapidly because it offers great design freedom in creating intricate lightweight shapes using lattice structures that offer numerous possibilities, including applications in aerospace, automotive, and electronics where mechanical properties are paramount. In this paper, inspired by the wing scale of the C. Rubi butterfly, unique uniform and density-graded gyroid lattice structures were proposed. This research designed the uniform gyroid lattice structure with two design configurations of unit cell sizes (4, 6, and 8) and solidity percentages (20, 30, 40, and 50) and density-graded gyroid with a solidity range of 20–80% in a constant volume of 30*30*30 mm. The designs have been modeled in nTopology software and manufactured using the Vat polymerization additive manufacturing technique with two printing orientations (0° and 25°). Two sets of the samples were printed, and one group was given postcuring treatment at 80°C for 2 hours. Quasi-static compression testing was performed to investigate the improvement in mechanical characteristics due to postcuring treatment and print orientation. The results indicate significant relationships between design parameters and mechanical performance. The density-graded gyroid lattice exhibits four times higher compressive strength than higher solidity uniform gyroid samples (UC-8-solidity-40 and 50%) when subjected to the same or less mass. In addition, debonding of connecting surfaces due to higher postcuring temperature, and better performance of horizontally printed samples have been addressed. Moreover, simulation and experimental deformation patterns for uniform and graded gyroid lattice structures have been displayed.