Yang, JinkyuYamaguchi, Koshiro2026-02-052026-02-052026-02-052025Yamaguchi_washington_0250E_28974.pdfhttps://hdl.handle.net/1773/55124Thesis (Ph.D.)--University of Washington, 2025Mechanical metamaterials, materials with architecture-driven properties, hold promise for applications ranging from aerospace components to soft robotic devices. Yet these engineered structures often face challenges in practical applications due to costly fabrication and fixed, non-adjustable properties once made. Origami-inspired design offers a path to overcome these limitations: by folding flexible architectures, metamaterials can gain reconfigurability and tunable behavior. In this dissertation, we introduce technical approaches for assessing reconfigurability, tunability, and controllability of origami-based mechanical metamaterials, focusing on Tachi–Miura Polyhedron (TMP) and Miura-ori patterns as model systems. Our goal is to advance these metamaterials toward the vision of highly reconfigurable origami-based mechanical metamaterials; materials that can be reshaped or repurposed on demand. To navigate the enormous design space of origami metamaterials, we develop a graph-based algorithm that systematically generates all geometrically valid TMP configurations. This approach avoids the combinatorial explosion that hampers brute-force searches, running roughly 20–100 times faster and enabling the analysis of much larger systems. By mapping the full range of configurations, our method also reveals highly heterogeneous, non-intuitive designs that would be impractical to discover otherwise. Next, we demonstrate a post-fabrication programming technique to fine-tune the metamaterial’s mechanical properties. By heating the TMP-based structures in a controlled manner, we reconfigure their internal folding geometry (zero-energy state) and achieve dramatic changes in stiffness and density. This thermomechanical tuning method increased the effective Young’s modulus by approximately 60-fold and reduced the material’s density by tenfold in experiments. Interestingly, we observed an unusual inverse correlation between stiffness and density, a beneficial trait for lightweight materials, and showed that Poisson’s ratio can be adjusted from negative (auxetic) to positive values. We also tackle the challenge of investigating the controllability of these compliant structures for deployment. Using a state-space model of a Miura-ori origami array, we analyze the system’s controllability to determine where actuators should be placed for the most effective shape change. The optimal actuation scheme predicted by our model was validated experimentally, yielding a fourfold increase in deployment efficiency compared to the least effective actuator configuration. This result demonstrates that even highly flexible metamaterials can be efficiently deployed through intelligent control strategies. Together, these advances establish a foundation for origami metamaterials that can be efficiently designed, adjusted on demand, and actively controlled as needed. By bridging geometric design, material tuning, and dynamic actuation, this work paves the way toward intelligent, adaptive origami-based structures with potential applications from aerospace and robotics to biomedical engineering.application/pdfen-USnoneControl theoryGraph theoryMechanical metamaterialOrigamiAerospace engineeringMechanical engineeringMaterials ScienceAeronautics and astronauticsThesis