Hierarchical cubic lattice structures with bending- and stretching-dominated cellular designs for enhanced buckling resistance

Buckling is a common failure mode in low-density strut lattices, limiting their mechanical strength and stability. This work presents a novel methodology to design and manufacture lightweight, buckling-resistant strut-based lattice structures by reinforcing buckling-prone members with hierarchical lattice unit cells—either stretching- or bending-dominated—without changing the strut lattice's relative density. Four types of lattice unit cells were examined: plate, honeycomb, strut, and TPMS solids and sheets. These were tested on single-cell cubic lattice columns with square cross-sectional struts. The resulting hierarchical structures were additively manufactured and experimentally evaluated, demonstrating significantly enhanced buckling performance. Design for additive manufacturing principles were applied, and structures with stretching and bending-dominated unit cells achieved higher critical buckling loads, with the square honeycomb cell lattice showing the highest improvement at 179 % over the baseline. This approach broadens opportunities for enhancing low-density strut lattices and developing novel buckling-resistant designs.