Voronoi-based metamaterials with controllable irregularities: Mechanical characterization of their disorder

Although widely adopted for designing metamaterials with unique properties, the periodic repetition of unit cells to form ordered structures captures only a fraction of the virtually limitless design possibilities that metamaterials offer.Naturally formed structures are usually characterized by irregular arrangements that provide them with peculiar properties, such as isotropic behaviour and the capability to manage internal defects, which periodic ones hardly show. Consequently, a design approach that could support the generation of both ordered and disordered structures would provide a more comprehensive strategy for exploiting metamaterials in multiple applications.This study tackles this challenge by introducing a metamaterials generation framework that exploits the concept of “disorder” in seed generation based on Voronoi tessellations to produce structures with varying levels of irregularity. The controlled “chaos” applied to the seeds is based on specific design variables whose correlation with the geometrical features and the mechanical properties under compression of the structures has been evaluated numerically and experimentally.The mechanical characterization has confirmed the effectiveness of the proposed design framework and its related approach in generating metamaterials with controllable properties. Applying disorder to an initial periodic seed distribution enabled the design of metamaterials with highly distinct responses to compression. Moreover, it has highlighted the challenges to be addressed to extend the framework and further validate it.