Optimal design of shape changing mechanical metamaterials at finite strains

Programmable metamaterials establish a new subset of metamaterials offering controllable and variablephysical properties. As metamaterials, they are artificial materials and exhibit exotic and counter-intuitive material behavior, but are more specifically tailored for engineering purposes. Whereas for metamaterials a mostly homogeneous layout of unit cells is considered, programmable materials are constructed by an individual distribution in order to satisfy custom intentions regarding a specific shape change under given loading conditions. In order to tackle this customization of material response, a computational optimization framework similar to topology or material optimization is proposed. Our work is based on a multiscale and data approach, allowing a broad range of application with different classes of unit cells and target functions under finite strains. In this contribution, we present the complete process chain from a parametrized unit cell to the final model of the programmable material, ready to be manufactured. We show numerical results with different unit cells and compare them to fully resolved simulations. Further, with the development of new generative manufacturing processes, the production of such programmable materials consisting of spatially varying cells has also become possible on an industrial scale. One example of lab-scale production is shown in the paper and compared to simulation results.