Tailoring simultaneous stiffness–damping of hexagon-based architected composites

Hexagon-based architected polymer composites are designed for simultaneous stiffness–damping properties. In particular, this study focuses on the stiffness–damping performance of filled hierarchical hexagon, irregular hexagon, layered hexagon. In addition, we propose spiderweb-inspired and interlocking hexagon-based designs to tailor the performance. In the process, we also consider the combination of the structure and filler materials to optimize the performance from the material perspective. These architectures are analyzed with the constituent materials being stiff polymethylmethacyrylate (PMMA) for stiffness and soft polyurethane (PU) for damping. Simulations are performed with RUCs of the architectures along with periodic boundary conditions to capture the properties. Quasi-static stiffness and complex modulus are determined from quasi-static tensile and cyclic loads at different frequencies. The figure of merit for performance is represented by \(|E^*| \times \tan \delta \). The performance is compared with that of the constituent PMMA and PU materials. The study shows that simultaneous performance can be tailored using hexagon-based simple yet elegant architectures. Among the architectures investigated, interlocking hexagon demonstrates superior figure of merit, achieving \(|E^*| \times \tan \delta =0.1\) GPa. While the predictions are for idealized geometries ignoring the manufacturing defects, the results highlight the potential of these architected composites and tailorability for applications demanding high-performance mechanical and damping properties.