A Methodology for Designing Auxetic Metamaterials for Adaptive Systems

To develop sustainable material systems, modern industries must create new, lighter systems using less materials without compromising their performances. Over the past thirty years, researchers from various disciplines have turned metamaterials as alternatives to natural materials. Among these materials, auxetics stand out due to their mechanical properties. Despite the fact that these materials have been experimentally used in architectural projects over the past two decades, design outcomes have predominantly relied on existing auxetic structures, limiting the use of them in architectural design solutions. This research aims to create a novel auxetic material system by focusing on the geometry of auxetic materials and their smart transformations, embedded within the morphological structures of these materials. The methodology of the study consists of four stages, including identifying geometrical parameters of auxetic metamaterials, setting the computational model, digital fabrication, and physical experiments. This study has progressed based on feedback from computational and physical models to evaluate the behavior of the system, which is passively activated by the applied forces. To evaluate the results, physical prototypes were produced for obtaining empirical data. Experiments applied on physical prototypes were conducted on two different materials, including biopolymer polylactic acid and thermoplastic polyurethane. Thus, the auxetic behavior of different materials were observed and compared. In the future, the integration of the proposed system with responsive materials will enable the development of adaptable systems for large-scale architectural applications.