Synergistically tunable active cooling and energy absorption in an open-celled honeycomb-corrugated hybrid sandwich structure

This paper proposes an open-celled honeycomb-corrugated hybrid sandwich structure that employs large-unit-cell corrugated cores as the primary load-bearing component and small-unit-cell honeycombs to augment the heat transfer surface area, thereby achieving multifunctional characteristics encompassing both active cooling and energy absorption. A test specimen was fabricated via 3D printing, and forced convection heat transfer experiments were conducted to validate the computational fluid dynamics (CFD) model. Concurrently, a finite element model for quasi-static out-of-plane compression was established. The corrugated plate volume fraction ω_c was varied continuously from 0% to 100% under fixed total porosity. Accordingly, the structure transitioned from a purely honeycomb core to a honeycomb-corrugated hybrid core and finally to a purely corrugated core. The effects of this variation on the heat transfer and mechanical performance were systematically investigated. The heat transfer results reveal that, when ω_c varies over a wide range from 0% to 54%, the overall Nusselt number based on the core height (Nu_H) of the structure remains comparable to that of the purely honeycomb structure, forming a high-performance “heat transfer plateau”. Pore-level heat transfer analysis further reveals a strong correlation (r = 0.941) between the fully developed Nusselt number (Nu_D) and the pore size distribution uniformity index, indicating that enhancing pore size uniformity and avoiding extremely small or large channels are key to optimizing the heat transfer performance of the hybrid structure. The out-of-plane compression results demonstrate that, within the heat transfer plateau region, the hybrid structure exhibits distinct mechanical advantages over purely honeycomb and purely corrugated structures: the specific energy absorption (SEA) increases monotonically with ω_c, the peak stress first decreases and then increases, and the crushing force efficiency (CFE) is significantly higher than those of both reference structures. By adjusting ω_c, a flexible trade-off design among active cooling, low peak stress, and high specific energy absorption can be achieved. These results demonstrate that, through the rational combination of sub-structures with different characteristic scales and functional advantages, the performance limitations of a single homogeneous structure can be overcome under lightweight constraints, enabling multi-objective synergistic optimization.