Structuring materials on a lower scale in relation to the component size (mesoscale), e.g., µm-cm, enables the design of almost arbitrary effective mechanical physical properties into so-called metamaterials [1]. Unit cells are the building blocks for these materials and their design enables unusual properties such as auxeticity (negative Poisson’s Ratio). By controlling either their non-linear mechanical behavior or the responsiveness to non-mechanical stimuli (such as temperature or magnetic field) a programmable material behavior can be designed. This means that properties are no longer fixed but a function of an external stimulus and allows us to implement logical conditions in the materials (e.g., a change from stiff to soft, variable Poisson’s Ratio, bistability) [2,3]. In addition, the variation of the geometrical parameters (e.g., beam thickness, angles) in the material can be used to control the macroscopic material behavior. However, geometrical restrictions from the manufacturing process should be considered in the design to guarantee producibility and scalability. We show the design process for such materials beginning with the desired mechanical functions and the unit cell geometries up to the distribution of the parameter in the macroscopic material computed with mathematical optimization methods for given target deformation behavior [4]. The behavior of the unit cells can be described by semi-analytical equations or using homogenization techniques. Different macroscopic material behaviors (e.g., shape morphing behavior) are controlled by the choice of geometrical parameters in the mesostructure. We present several unit cells that can be created by different manufacturing methods (fused filament fabrication [2,3], foil stacking [4]) and that are controlled by different triggers (strain, temperature, alternating magnetic field) as well as arrays of several of these unit cells. The designed shape morphing behavior within these structures is analyzed with finite element simulations and validated with experiments on physical demonstrators. The presentation shows how the concept of mechanical metamaterials can be extended by considering possible stimuli-excited changes in the mesostructure during the design process. The resulting programmable materials can be beneficial for applications in which a customized or personalized material behavior is necessary or when the behavior should adapt to environmental conditions. REFERENCES [1] Kadic et al. 3D