UC Irvine

Architected materials (or metamaterials) are engineered multiphase (composite) or single-phase (cellular) materials with carefully controlled and optimized topological phase distributions, which can result in combinations of properties not normally found in nature. Over the past two decades, a wide variety of metamaterials have been developed for mechanical applications, achieving exceptional combinations of high strength and stiffness, high energy absorption and high fracture toughness. Optimal design of the topology plays an essential role in achieving exceptional mechanical properties of architected materials. Whereas traditionally the most heavily investigated designs have all been truss-based, the rapid development of additive manufacturing technologies over the past decade has spurred interest in more complex topologies, notably shell-based periodic architected materials based on triply periodic minimal surfaces (TPMS). While TPMS-based architected materials have been shown to possess combinations of high stiffness, strength, energy absorption and notably better mechanical properties than their truss-based counterparts, they are generally difficult to manufacture in a scalable fashion, thus limiting their potential applications in structural components. Shell-metamaterials with stochastic spinodal topologies (where the smooth continuous shell is defined as the interface between two spinodally decomposed phases) have the potential of combining TPMS-like performance and exceptional scalability. In this thesis, we experimentally investigate the mechanical performance of shell-metamaterials with spinodal topologies, in the form of cellular materials, as well as in the form of reinforcement phase for composites, manufactured through both additive manufacturing and self-assembly techniques. We conclude that architected materials with spinodal shell topologies combine remarkable specific stiffness and strength, a long flat plateau after yielding, intriguing toughening mechanisms and potential for self-assembly. These results suggest that architected materials with spinodal shell topologies are excellent candidates for mechanical and multi-functional applications.