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.