Drop-weight impact characteristics of additively manufactured sandwich structures with different cellular designs

• Published in: Materials & design 2018-05, Vol.145, p.122-134
• Main Authors: Beharic, Amer, Rodriguez Egui, Rafael, Yang, Li
• Format: Article
• Language: English
• Subjects: Additive manufacturing; Cellular structure; Drop-weight impact; Energy absorption; Sandwich panel
• ISSN: 0264-1275; 1873-4197
• DOI: 10.1016/j.matdes.2018.02.066

•The quasi-static properties of the sandwich structures exhibit insignificant correlations to impact properties•The drop-weight impact performance of sandwich structures is dependent on the core geometry design•Re-entrant auxetic core designs can be tailored to exhibit high energy absorption, but might exhibits high response forces•The BCC core designs exhibit good single-impact performance due to low mechanical strength and large energy dissipation area•The octet-truss core designs exhibit low volumetric impact performance and low residue retaining ability [Display omitted] In the design of sandwich panels with cellular cores for energy absorption, the geometrical effect of the cellular core design has not been investigated in details previously. In this work three cellular core designs, including re-entrant auxetic, octet-truss, and BCC lattice, were experimentally investigated for their performance under low-energy impact as sandwich structures. Samples with different cellular core designs were fabricated by laser sintering additive manufacturing process using Nylon 12 as material, and evaluated by drop weight testing under multiple strikes and at two levels of elevated temperatures (93°C and 121°C). It was found that beside relative densities, the geometrical design of the cellular cores could also significantly influence the impact energy absorption performance of the sandwich structures. It was also found that the impact energy absorption of the cellular structures investigated in this study does not have a significant correlation with either the quasi-static mechanical properties or the temperature. In addition, the auxetic cellular structure exhibits optimal overall energy absorption performance compared to both the octet-truss and the BCC lattice.