A Novel Lattice Structure for Enhanced Crush Energy Absorption

Abstract

Lightweight and stiff lattice structures are good energy absorbers. This study evaluates the energy absorption capacity of a few common lattice structures printed out of PLA using fused deposition  modeling and proposes an improved lattice structure. Simple cubic (SC), honeycomb (HC),  body-centered cubic (BCC), and  novel PeckGy80 (PG80) lattice structures were subjected to compressive tests. The quasi-static load-displacement  behavior of lattice specimens was characterized in terms of specific energy absorption and crush load efficiency. The damage mechanisms were then related to energy absorption. Cracks and brittle fractures occurred in all lattice structures during the crush test. Different lattice structures induced different damage mechanisms,  significantly affecting their energy absorption. SC lattice structure showed structural separation at a small displacement, rendering it an ineffective energy absorber. BCC and HC lattice structures demonstrated almost identical shear band failure modes. The PG80 lattice structure, although made of brittle PLA, displayed progressive failure from the bottom layer to the upper layers, exhibiting both a high peak load and  stable post-yield behaviour. This damage mode enabled the PG80 lattice to be far superior in terms of specific energy absorption to HC, SC, and BCC lattice structures.

Keywords

• 3d printing
• energy absorption
• lattice structures
• pla
• quasi-static crush