Low-velocity impact performance of lattice structure core based sandwich panels

This paper outlines the findings of a study on a range of stainless steel and titanium alloy lattice structures manufactured using the selective laser melting technique. The effect of varying key manufacturing parameters on the properties of lattice strands was studied through a series of single-filament tensile tests. The resulting failure mechanisms were investigated using a scanning electron microscope. The resulting observations have shown that the properties of these lattice strands are determined by the laser energy during the manufacturing process, which in turn is controlled by the laser power and laser exposure time. The quasi-static and low-velocity penetration behaviour of lattice core-based sandwich panels has been examined, and an aluminium foam and an aluminium honeycomb were chosen to benchmark their performance. The impact resistance of the lattice core-based sandwich structures were shown to be dependent on both the manufacturing parameters and lattice unit-cell geometry of the lattice structure. The impact resistances were improved by increasing manufacturing laser energy and lattice core density. A series of drop-weight tests at velocities up to 6 m/s have shown that the penetration behaviour of the titanium alloy lattice cores and the aluminium honeycomb cores is similar.