The effect of topology on the quasi-static and dynamic behaviour of SLM AlSi10Mg lattice structures

Additive manufacturing (AM) techniques such as selective laser melting (SLM) enable the fabrication of complex metallic lattice structures. By tuning geometric and topological parameters, these structures can be manufactured to exhibit a range of useful properties, including excellent strength-to-weight ratios and energy absorption capabilities. While the effects of these parameters on various aspects of AM lattice performance have been previously studied, such as the effects of manufacturability, material selection and geometric parameters on the quasi-static performance of AM lattice structures, the effect of topology on the dynamic behaviour of SLM AlSi10Mg lattice structures remains relatively unexplored. Lattice structure specimens with five different topologies were manufactured using SLM AlSi10Mg and tested under quasi-static and dynamic loading conditions. The tested topologies were body-centred cubic with (BCCZ) and without (BCC) z-struts; face-centred cubic with (FCCZ) and without (FCC) z-struts; and body and face-centred cubic with z-struts (FBCCZ). A numerical model was developed to investigate failure modes and collapse mechanisms. Specimens were found to fail by the emergence of diagonal shear planes, and the orientation of which was dependent on topology, due to the uneven concentration of stress in struts across the structure. No significant rate sensitivity was identified for any of the tested topologies in the range of tested strain rates. The FCCZ topology was demonstrated to provide the greatest efficiency in terms of both strength-to-weight and stiffness-to-weight ratios. These results assist in the characterisation of the dynamic behaviour of SLM AlSi10Mg lattice structures and contribute to their further commercialisation.