Shock compression of auxetic metamaterials made by additive manufacturing

This proposal concerns to study the dynamic response of additively manufactured auxetic metamaterials made from metal. This particular class of lattice structure metamaterials displays unconventional material behaviour: it contracts laterally rather than expands upon compression. As a consequence, specific strength and stiffness are potentially better than for other lattice or porous materials, which makes these materials interesting for light-weight crash absorbers. An important question in this context is, from what critical velocity onwards the auxetic structural response is replaced by a cell collapse mechanism. Real-time visualization of this mechanism in the bulk of the material can only be performed with X-ray imaging. Preliminary investigations of the dynamic effects have shown that critical velocities are ~100-200 m/s, which can be attained with the gas gun setup at ID19.