Effect of cell wall corrugation on the effective elastic properties and in-plane compressive behaviour of honeycomb metamaterials

The in-plane compressive performance of lightweight honeycomb metamaterials is often constrained by susceptibility to buckling instabilities. Here, out-of-plane corrugation is introduced to control these instabilities and tailor the honeycombs’ mechanical response. A combined numerical and experimental framework investigated the influence of three corrugation profiles (sinusoidal, triangular, and trapezoidal) on additively manufactured triangular and Kagome honeycombs. A parametric finite element study mapped the design space, while targeted physical testing validated the predicted macro-structural collapse mechanisms. To isolate the purely geometric effects of the architecture, all investigated configurations were strictly constrained to a constant relative density (ρ=0.2). By keeping the mass constant, we demonstrate that introducing out-of-plane corrugation significantly stiffens the cell walls. This geometric stiffening alters the macroscopic failure mechanism; specifically, sinusoidal and triangular corrugations suppress unstable shear banding in favour of stable layer-by-layer collapse, leading to substantial performance gains. Compared to flat-walled baselines, the best corrugated designs achieved up to 207% higher specific energy absorption and 152% higher peak stress within the tested strain range. These results indicate that architectural design of cell walls is a promising pathway for overcoming traditional performance limits and developing next-generation metamaterials with tunable mechanical properties.