An innovative hierarchical design of hybrid meta-structures for longitudinal waveguides

This study introduces a hierarchical design methodology for functional waveguides, utilizing 2D honeycombs with stepwise geometric variations as foundational microstructures, focusing on the tunability of time-domain responses under impact loads. By maintaining constant homogenized density, our approach manipulates stiffness along the wave propagation path. A semi-empirical model, based on curve-fitting to finite element solutions, accurately predicts dynamic responses including wave propagation speed, force transmission to supports, and reflected velocities at the tip. Using Ashby plots, we develop a modular strategy for assembling waveguide bundles – or even bundles of bundles – to meet specific performance criteria, enhancing design efficiency. This framework, ideal for integrating with machine learning and multi-objective optimization, enables tailored designs for applications ranging from impact protection to smart actuation in aerospace, automotive, and biomedical sectors, marking significant advancements in material design for dynamic environments.