Metamaterials constitute a class of engineered materials whose properties are primarily governed by their internal architecture rather than by the chemical composition of the base material [1]. Through tailored geometry and topology, mechanical as well as thermophysical characteristics can be achieved that are not attainable with conventional materials. This contribution provides an overview of metamaterial concepts and focuses on two representative structural classes: auxetic structures [2] and triply periodic minimal surfaces (TPMS) [3,4]. The objective is to demonstrate the role of simulation-based methods in the design and optimization of metamaterial-based material architectures. Auxetic structures offer enhanced design freedom in structural mechanics and are of interest for applications such as energy absorption, vibration mitigation, and adaptive lightweight components. TPMS structures feature smooth periodic geometries and high surface-to-volume ratios, making them attractive for thermophysical applications, for example in compact heat exchangers. For auxetic structures, parametric unit cell models are investigated using finite element methods (FEM) to evaluate effective stiffness, deformation behavior, and energy absorption. The influence of geometric parameters on the macroscopic mechanical response is systematically assessed. TPMS structures are analyzed by means of computational fluid dynamics (CFD) simulations with a focus on heat transfer performance, temperature distribution, and flow-induced pressure losses. The results indicate that both auxetic and TPMS-based architectures can be efficiently tailored to application-specific requirements using advanced numerical simulations. The presented approaches are transferable to a wide range of metamaterial concepts and support simulation-driven material and product development.