Compressive performance and fracture mechanism of bio-inspired heterogeneous glass sponge lattice structures manufactured by selective laser melting

Abstract

High precision lattice structure (LS) shows great potential applications in aerospace, acoustic, biomedical, and wearable products due to its multifunctional characteristics and excellent mechanical properties. Inspired by lightweight, high-strength, and high-stability glass sponges (GSs), a unique circle-/grid-like heterogeneous glass sponge lattice structure (GSLS) was successfully designed and manufactured by selective laser melting (SLM) with Ti6Al4V alloy. Compared with the commonly used body-centred cubic (BCC), face-centred cubic (FCC), honeycomb and diamond LSs, GSLS displays the strongest compressive properties (E = 1560 MPa, σmax = 40 MPa, σy0.2 = 34 MPa, W = 5.95 J). The normalised elastic modulus and normalised compressive strength of GSLS are almost 1.4 and 1.3 times, 2.6 and 2.4 times, 2.7 and 3.5 times, 18 and 8.3 than that of FCC, BCC, honeycomb, and diamond LSs, respectively. Most importantly, unlike the 45° diagonal shear failure of homogeneous BCC and FCC, the FEA simulation reveals that the heterogeneous unit cell in GSLS can enhance the strut connectivity, disperse the stress, and exhibits a unique fracture mechanism of cell-after-cell and layer-by-layer. The fracture mechanism of GSLS can improve the load-bearing capability, maintain strength, and protect its interior and entire integrity during compression.