Metafluids – Harnessing thick shell instability to program fluids

Inspired by mechanical metamaterials, we introduce the concept of a metafluid - a fluid where the mechanical response is programmed via embedded highly deformable elastic elements. In particular, we introduce into the fluid thick elastomeric spherical shells that buckle under external pressure. We first show that the highly nonlinear local behavior of these unit cells makes the global response of the fluid radically different from that of ordinary liquids in terms of compressibility, viscosity and phase transformation. Then, we show that these fluid characteristics can be controlled by tuning by the geometry of the embedded shells. Metafluids thus provide a unique platform to enhance the capabilities of all hydraulic networks, by enabling energy absorption, disturbance rejection and even logic functionalities inside of the fluid itself.