Controlling the response of lattice metamaterials to impulsive loads by spatial distribution of mass

The advent of additive manufacturing (AM) has blended the design space for materials and structures. One such case are lattice metamaterials, which promise lightweighting while providing structural strength. This interest has led to an increase in the number of studies that are investigating responses of metamaterials to static and dynamic loads. Impulsive loads are typically ameliorated by crushing of the lattice, which provides excellent energy-absorption, while static loads are supported with unit cells sufficiently far away from the onset of buckling or yielding. However, in statically-loaded structures simultaneously enduring impulsive loading events, the superposed impulses must be withstood without leveraging plastic deformation and compaction, which effectively means only elastic deformation. For a class of impulse shapes associated with laser-driven shocks, our key findings show that the pulses can be attenuated by adding thin solid skins covering the lattice. Additionally, moving mass between the lattice beams and the solid skin allows the attenuation to be partially uncoupled from the mass of the combined structure; low-mass samples provide greater attenuation than high-mass samples depending upon where the mass is located. All else being equal, mass in the solid face sheet is more important than mass in the lattice for attenuation.