The quasi-static and blast loading response of lattice structures

A range of metallic lattice structures have been manufactured using the selective laser melting (SLM) rapid manufacturing technique. The lattice structures were based on [±45°] and [0°, ±45°], unit-cell topologies. Initially, the structures were loaded in compression to investigate their progressive collapse behaviour and associated failure mechanisms. Tests were then undertaken at crosshead displacement rates up to 3 m/s in order to characterise the rate-dependent properties of these architectures. A series of blast tests were then undertaken on a ballistic pendulum in order to investigate the behaviour of lattice structures under these extreme loading conditions. During the compression tests, a buckling mode of failure was observed in the [0°, ±45°] lattice structures, whereas a stable progressive mode of collapse was evident in the [±45°] structures. The yield stress of the lattice structures exhibited moderate rate sensitivity, increasing by up to 20% over the range of conditions considered. The blast resistance of the lattice structures increased with increasing yield stress and has been shown to be related to the structures specific energy-absorbing characteristics. An examination of the lattice samples indicated that the collapse mechanisms were similar following both the compression and blast tests.